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Population Dynamics of Exotic Insects B'j1 Research Institute, TURNBULL1 A. L. Canada Department of Agriculture, One of the most conspicuous features of introductions of exotic species for biological control is that a large proportion of even the most carefully prepared introductions fail. Though the organisms are usually carefully selected for compatibility with known features of the physical environment of the colonial site and known foods are abundant in the new environment, only about 1 of every 10 introduced species succeeds in producing viable populations in new areas, and many of these gradually diminish and disappear. The causes are unknown; speculative reasons are usually given. Climate is the usual scapegoat, especially in regions such as Canada, wh~re winters tend to be severe, or California, where excessIve heat or dryness is not unusual. But most species pass rigid tests of these factors before they ~re. introduced; thus these "explanations" tend to lack convlctlon. These organisms were deliberately introduced into ca~efully prepared environments, and few would long survive if deprived of tender loving care. Thus they cannot be considered to be truly established on this continent in any real sense of the word. In addition to these organisms an even larger assemblage of organisms was accidentally introduced. For .this group no sites were deliberately prepared; they recel.ved no loving care, and were entirely dependent for survival on thcir own resources. Many species of this group are now thoroughly established in North America, and many now constitute major problems. Largely to combat this latter group, a further assemblage of organisms has been and is being introduced. This group comprises organisms that are generally known as agents of biological control. This third group. may be initially cultured to some degree, but eventually Its membcrs too are cast loose to fend for themselves. Another favorite explanation is that the new environment lacks some unknown but essential requisite of the colonist species. If the critical element cannot be discovered, this explanation is not very satisfactory. Another conspicuous feature of biological control introductions is the occasional species that establishes an extremely viable population with great alacrity. ~~om quite small colonies, often introduced under condltlo.ns far from optimal, some species have achie;ed substantial populations within a very few generatIOns. Clausen (1951) examined several of these cases and concl.uded that fully successful exotic parasites or predators achieved full commercial control of their hosts within 3 years or Once an exotic species is thoroughly established in a new environmcnt there is no reason to suspect that its population dynamics differ in kind from those of a native spccies. After all, exotic and nativc are relative terms; many of our so-called natives originally made their way hcre from other continents, after which time further spcciation mayor may not have occurred. Thus, when we speak of the population dynamics, or of any other fea- 3 generations of colonization. This conclusion means that ture of exotics, we are rcferring to the processes that take place during the establishment period. However, the estabIishmcnt period is of indefinite duration, and it is difficult to identify criteria that indicate when it is complete. However, of the species introduced for biological control, considerably more factual observations of the colonization and early establishment process are available. Therefore, in general I propose to discuss some of the problems of introducing exotic organisms for biological 1 Present address: Dept. of Biological Sciences, Simon Fraser University, Burnaby 2, B. C. Ontario control, to see if these problems have any general applications. Exotic organisms playa very large role in our everyday lives; probably about 900/0 of the common ~oods produced on this continent as well as a large portton of our fiber crops, ornamental flowers, shr~bs, .a~d trees, are derived from plants or animals of exottc ongms. lfost species that were accidentally introduced into North America remained undetected for some time after their arrival, and it was not until establishment was well along that their presence and foreign origins were detected. A consequence is that very little is known of the population processes of such species in their period of colonization. There are, of course, a few exotic species that made themselves conspicuous by becoming pests very early after their arrival, and much is known about these species. But these are a small minority and constitute special cases. A far greater proportion have not distinguished themselves in any way and have become quite innocuous ancl interesting components of our fauna. Confirmation of this phenomenon may be found in Lindroth (1957). Most of you never have heard of most of the species in his lists of European invaders of North America. Belleville, these insects built up their numbers from a handful to the limit of their food resources within 3 generations. Clausen's observations were challenged on theoretical grounds (Thompson 1951), but most subsequent experience supports his conclusions. Less conspicuous but commonly occurring in the practice of biological control are the exotic species that successfully establish permanent populations on a. colonial site only after a prolonged struggle. These specIes rarely achieve any prominence in the new community, and usually form small localized or wides~re.ad, d~ffuse. populations. Their impact on the pre-exlstlllg bIOta IS small, and they rarely achieve commercial control of their prey (or host) pests. In the orthodoxy of biological contr?1 they are said to achieve "partial". control, on the b~sls that if they are present on the sIte, and are attacklllg pests, they must be contributing in some degree to the suppression of pest populations. The reasons for these differences have always biological control workers. Most species seem capable of thriving in the new territory, but the mains that most of them fail to do so, even though ous efforts are made to give them every advantage. It cies cies fail 333 baffled equally fact restrenu- is highly probable that accidentally introduced spefall into the same categories. Undoubtedly many speof the potential immigrants that arrive in our country to establish permanent populations. A much smaller number establish small, localized populations that become innocuous and interesting elements of our fauna. A wry few of the species that arrive succeed extravagantly. These latter species are often very disruptive of our native and cultured communities and constitute some of our most serious and damaging pests. There is at present no known a priori way of predicting into which category a potential immigrant will fall, nor can we even say after the event why it turned out as it did. Until we are able to supply such explanations we cannot be said to understand even the barest essentials of the population dynamics of exotic species, or to approach intelligently the problems of either excluding damaging exotics or of introducing beneficial ones. TIlE COMPETITIVE DISPLACEMENT PRINCIPLE There is a substantial piece of research published over the past 5 years or so, which, though it has not escaped attention, has a bearing on this problem that may have been overlooked. This is the work of DeBach and his associates on the introduction of various species of exotic parasites of the aphelinid genus Aph:ytis to control the citrus red scale in California (DeBach and Sundby 1963; DeBach 1966). The phenomenon that DeBach observed he has designated the "Competitive displacement hypothesis." The concept involved has a long history under the names of "Gauze's law," "Grinnell's axiom," the "competitive exclusion principle," and various others. DeBach and Sundby (1963) have reviewed the history of the concept. De Bach briefly stated the hypothesis as follows: "different species having identical ecological niches (i.e. ecological homologues) cannot co-exist for long in the same habitat." The process involved in this concept has been repeatedly observed. When two species of closely similar habits, behavior, life histories, and, particularly, food needs are confined in a homogenous, closed environment, one of the species inevitably displaces the other. Which of the two species emerges the victor seems to depend on the particular structure of the environment and on external physical factors such as temperature, etc. On the other hand, if two species that significantly differ in these respects are confined in similar environments, both can co-exist indefinitely. It was debated for many years whether this concept was applicable to natural, free-living environments, or whether it was a product of closed, artificial, homogenous environments created in laboratories or in food-storage depots. While there was little unanimity about it, the general consensus seems to have been that it had little significance, or if it had, it would be virtually impossible to detect in natural environments. The concept was therefore considered by many to be less than helpful to the understanding of natural populations. For many years the hypothesis hung more or less in limbo, neither proven nor disproven. It held an ambiguous place in the conceptual arsenal of theoretical ecologists; it was frequently evoked in theoretical discussions, but its evocation lacked consistency and was always open to challenge. Now, through a series of patient and careful observations rarely equaled in the history of biological control, DeBach and his associates have convincingly demonstrated that the process does occur in nonconfined, freeliving organisms, at least under certain circumstances. What DeBach observed was essentially this: Apfryfis clzrysolllplwli (.Mercet), a parasite of California red scale, was accidentally introduced into California about 1900, probably from the Mediterranean region. By 1920 it .w:~s widely distributed in the citrus areas of southern California over the range of its host. In 1948 A. lingllancl1sis Compere was introduced from south China. This species is very similar in every respect to A. chrysomPhali. Immediately after A. lillgllallcllsis was introduced it was apparent that it was displacing A. chr.1'somPlwli near th,' areas of release. By 1959 A. chr)'solllphali was reduced to a minor species surviving in small pockets only in the south coastal region. In 1956-57 another ecologically and biologically similar species, Aphytis lIIclillUS DeBach, was introduced from India and West Pakistan. It was shortly evident that ,"melinlls was emphatically successful in interior areas, where it rapidly displaced A. lillgllallcsis. But though A. 1IlclillllS was thoroughly colonized in coastal areas it completely failed to established populations there, though it was known that the climate in that area was eminently favorable. Thus A. lillgllallcsis continued to dominate in coastal areas. These observations revealed three occasions in which displacement (or exclusion if you prefer) occurred: 1. .1. lillgllallcllsis displaced A. chrJ'somphali over most of its range; 2. A. 1IlelimlS displaced A. lin91lUlll!IIsis in interior areas; 3. A. lillgllallcllsis displaced, or excluded, A. melililtS in southern coastal areas. It is important to note that parasites of the red scale other than Aph},tis species occur in all areas. Comperiella bifasciata Howard and Prospaltcllll flcmieillsi Tow,'r are prominent among them. But these two species di ffer from each other, and from Aplzytis species, in various respects. Both of these species persist in all areas, hut one is the more abundant in some parts of the range and the other in the remainder. Neither was seriously disturbed by the Aphytis species. These observations were accompanied by a series of well-designed laboratory and field experiments which confirmed the observations and to a large degree explained them. It was shown that when any two "ecological homologues" were brought together in a common environment (a) one species always displaced the other within 8 generations; (b) the winning species could be altered hy making small changes in the environment; (c) displacement occurred in the presence of a surplus of food, i.e., food shortage is not a requisite for displacement; (d) differences in the relative fecundity and survival of immature stages, as reflected by the F, progeny production, appeared to determine which species was the winner. On the other hand, when two species "with only slight ecological differences" were brought together in a common environment the results were ambiguous. In some instances one of the species was displaced. In the lastmentioned cases either of the species could be the one displaced, depending Oll external circumstances. INTERPRETATION OF COl\IPETITII'E DISl'LACE1fENT We now know that the processes which gave rise to the enunciation of the competitive displacement principle do occur in nature, at least under the exceptional circumstances of the coming together of closely related and very similar species, each of which is endemic to widely separated, mutually inaccessible areas of the world. The only point in question now seems to be how this process is interpreted. 334 Virtually all authors who have discussed the competitive displacement principle have done so in terms of identity of ecological niche. Indeed the two concepts, displacement and the niche, have represented opposite sides of the same coin. Both concepts are generally considered to have originated with Grinnell in a series of papers between 1904 and 1928. From an initial tentative statement Grinnell progressively developed the idea into essentially the same form that it is understood today. In 1904 Grinnell stated "Two species of approximately the same food habits are not likely to remain long evenly balanced in numhers in the same region. One will crowd out the other." By 1917 this tentative, much hedged statement had become "It is of course axiomatic that no two species regularly established in a single fauna have precisely the sanll: niche relationships." This statement, which is much more positive than the former one, represents a solidifying and a narrowing of the concept. Finally, in 1924 Grinnell defined the niche: "In studying these matters I ha\'e come to use the term 'ecologic niche.' This expression is intended to stand for the concept of the ultimate distributional unit, within which each species is held by its structural and instinctive limitations." So here we have both concepts, competitive displacement and the ecological niche, unequivocally stated. No one has since added much to these concepts. We can see the developing logic that led to these con('epts. Empirical ohservations led to an initial, tentative statemcnt. Twenty years later this statement solidified into a formalized axiom. The concept of the niche was a necessary invention to support the axiom. If we accept as axiomatic that two species making identical demands on an environment cannot simultaneously exist in that environnll'nt, we ll\ust conclude that each kind of organism present in an association of organisms must possess a uniquc set of environmental requisites. This is the niche. The niche, therefore, is a collective term for all the kno\\'n and unknown requisites of the species in a given community. Thus if we spcak of species having identical niches (i.e. ecological homologues), we are proposing that two different kinds of organisms need precisely the same things from the environment, down to the most minute detail. This proposition seems extremely unlikely. The tt~rms of the axiom itself preclude the possibility of two sympatric species evolving identical niches. And for allopatric species to evolve identical niches would surely 1'l'(juire that their ancestral stock possess equivalent evolutionary potential, and be subjected to identical environmental pressures in geographically separate areas. This hypothesis seems to be pressing credulity too far. Even though we might admit its theoretical possibility, we would have to concede its extreme improbability, and thus its very rare occurrence. Now we do not know how rare the phenomenon of rompetitive displacement is. But from DeBach's work wc do know that it occurs. We also know that in this one hiological control project it occurred three distinct times. I suspect that this project was the only occasion in which the interactions of introduced species with the resident hiota were observed carefully enough to detect the process of displacement. If the process occurrcd three times in the single adequately observed case, it is probable that it has also occurred frequently in many other, less adequately observed caSt's. Therefore, competitive displacement may be a fairly common occurrence, particularly in cases where species that evolved in other associations are introduced to new areas. This, of course, includes the case of colonization of exotics. 1£ it is a common occurrence it is improbable that identity of ecological niches is involved. Nor does it seem necessary to the concept that the niches be identical in all respects. If they are alike in only one respect, that fact would seem enough. If two species share a single common environmental requisite and one species for any reason exploits that requisite more efficiently than the other, this species should gradually take over a larger and larger proportion of that requisite and thus progressively deny it to the other. Displacement would follow. Grinnell tacitly admits this possibility in his early work. In 1904 he talked of "two species of approximately the same foods ... ." Foods may be an element of the niche but they are certainly not the whole thing; identical foods do not imply identical niches. Moreover, he applied the adjective "approximately," meaning that even foods need not be identical. De Bach conceded the point more directly. He said "If only one essential component of the niches of two species, such as food, is identical, then these species have identical niches insofar as food is concerned" (DeBach 1966). In this statement, after defining the niche so that it is virtually all inclusive, De Bach contracted his definition to a single element, to keep his formally stated axiom within the bounds of reality. However, DeBach states his position clearly, and I do not quarrel with him. But the thing that concerns me is why these authors, and most others that discuss this concept, persist in talking of "identical niches" when they are clearly referring to a single environmental element. To do so places quite unjustified emphasis on the need for exact identity of the two species. "Identical" is a precise term,-it means "exactly thc same." Different species that have cxactly the same environmental requisites arc hard to imagine, and if two such should mcet in a common environment neither could displace the other except by chance, for neither could possess a consistent advantage. It is a primary requisite of competitive displacement that the two species must not be identical, but in fact must be different. It is only by being different that one can win and maintain an advantage over the other and thus displace it. As a result of this concern over exact identity, the concept of competitive displacemcnt has come to be considered a unique phenomenon of rare occurrence. Two species with identical niches must be rather rare, even if they are siblings. Similar niches-yes; identical-no. On the other hand quite different organisms that possess one or more common requisites must be plentiful, and must frequently meet in common environments when they are arbitrarily moved about from one zoogeographic region to another. For competitive displacement to occur, two opposing conditions are necessary. The organisms involved must have some (at least one) elements in common, i.e., there must be some degree of similarity. On the other hand there must be some difference between them. Now how similar or different do they have to be? This cannot be answered, except to say that the more similar they are, i.e., the more elements they have in common, the more likely is displacement to occur, as long as one difference, no matter how slight, is left. Thus DeBach's Aphytis spp., which were very similar, were very vulnerable to displacement. 335 On the other hand, the less similar they are, the less they have in common, and the less likely is displacement to occur. Thus, in DeBach's work, Prospaltella and Comperiella, which are substantially different, could coexist with each other and with Aphytis in some situations, but in other situations either one could be displaced. Moreover, in some climatic zones Prospaltella was materially more abundant than COlllperiella, and in other zones their position was reversed. This fact clearly indicates to me that these two species were competing to some degree and that the advantage changed from one to the other under the influence of changing environmental clements. Therefore, these species could maintain a state of dynamic balance, but at all times either one or the other, or perhaps both, may be suppressed below their maximal potential by competition, and both are in some danger of displacement. Seen in this light we can recognize that competitive displacement is not a separate or unique phenomenon. It is merely an extreme case of the general concept of interspecific competition, and can quite well be circumscribed by that concept. It probably occurs frequently when species that evolved in different faunas are indiscriminately mixed, because such species have had no opportunity to evolve life processes that permit them to avoid competition. RESISTANCE OF COM1I1UNITIES TO INVASION Does this interpretation of the "competitive displacement principle," or the interspecific competition principle, throw any light on the varying success of exotic species in colonizing new territories? I believe it does: most exotics that seem well adapted in all ways to colonial sites fail to secure lasting colonies. Is it because they possess too many requisites in common with endemic species and are thus "competitively excluded?" Is it not to be expected that most long-established communities will have evolved animals adapted to exploit most of the niches that the community has to offer? Is it not likely that species that have evolved under the precise conditions of a given community will be more efficient in exploiting the available niches of that community than some exotic interloper that evolved in some other, different community? The probabilities all favor the incumbent species. Thus it is unlikely that many interlopers can succeed; most will be rejected no matter how tolerant they may be to the physical conditions encountered. But the aforementioned conclusions are based only on probabilities. The improbable cannot be excluded; it is bound to turn up eventually. In the long history of introduction of exotic species it has turned up repeatedly. Some immigrant species do have certain advantages at least at times, or in certain parts of the community, that permit them to achieve limited victories over resident species. In these cases the advantage is rarely all on one side, and a prolonged struggle may result which no doubt generates heavy selection pressures on both organisms. Eventually either of the species may be eliminated, or a measure of adaptation may develop through which the two species divide the niche and thus minimize direct competition. In the latter situation the invading species can secure a firm but limited foothold in the colonial territory with little opportunity to expand further. Most of our established exotics fall into this category. Finally, there are a very few cases where some immigrant species either possesses a distinct advantage over an endemic species or where they find unoccupied niches that they are able to exploit virtually free of competition. Such species have an enormous advantage over endemic species. The endemic fauna will be ill adapted to cope with them, and normal community processes of hOI11('ostasis will be absent. Until they reach the limit of fond resources their rate of population expansion is limited only by their inherent rate of increase. Therefore, such species become either major pests or major agents of biological control, depending on their mode of life. THE RELE\'AXCE OF COMPETITIVE DISPLACEMENT TO BIOLOGICAL CONTROL The relevance of the competitive displacement (or exclusion) hypothesis to the practice of biological control is self evident. The importation of exotic entomophages is the chief method through which biological controls are practised in North America. The philosophy behind this practise is that community stability is a product of the diversity of the environment. By introducing many species of entomophages we hope to add to the diversity, an(! thus to the stability of the community (Huffaker am! Messinger 1964, p. 50, Balch 1960). But the work discussed here demonstrates that the men' introduction of a species to an already well inhabited environment is unlikely to increase the number of species the environment supports. The results of introductions in order of decreasing probabilities arc: the introduced species is excluded by the competition of an incumhent species; the introduced species divides the site with an incumbent species; the introduced species displaces an incumbent species; or the introduced species finds a vacant niche and becomes established without displacing any incumbent. Only in this last, and least probable situation, is the diversity of any part of the site increased. The displacement of part or all of a site will acter of the ecosystem that such a change will tion is remote. one species by another in eithl"almost certainly change the charto some extent. But the chance stabilize or reduce a pest popula- I can imagine only two mechanisms by which an incumbent species would be displaced by an immigrant: the immigrant directly attacks and demolishes the incumhl'nt species; or the immigrant species 1110nopolizes some environmental requisite, thus denying it to the encumbent population. In the practice of biological control the former situation is usually anticipated and avoided' the second situation is probably the usual cause of displace~lent. DeBach found that competitive displacement frequently occurred in the presence of a surplus of food (prey). In such cases some other niche requisite must be involved, and whether a displacement based on some other resource would increase or decrease the utilization of prey can be only a matter of chance. Therefore, DeBaeh's work may explain why so many biological control projects have failed. The chances of establishing a foreign entomophage in a new environment are always small, and even if this hurdle is overcome the chances of the immigrant's producing any beneficial ~ffcct on pest abundance is also small. Nevertheless, introduced entomophages historically have produced conspicuous benefits in pest control. Long-shots do occasionally payoff. Whether the few successes obtained are worth the many failures inherent in such longodds gambling is debatable. Some rather imaginative balance sheets of benefits and costs have been drawn up suggesting that they are (DeBach 1964, p. 13). But anything we can do to shorten the odds will surely increase 336 our chances of success. As is usual in gambling situations, shortening the odds consists of obtaining inside information. In this case we need information permitting us to recognize vacant niches and the kinds of organisms that arc needed to fill them; to understand the mechanics of competition so that we introduce only organisms that have some chance of establishment in the face of incumbent species; to gain some assurance that the immigrant species, once established, will produce a beneficial effect on pest populations. single species-our crop; not with stabilizing pests, but suppressing them. For these purposes we seek specific agents to carry out specific tasks. The chances of finding such agents without knowing what characteristics they should possess are not impossible, but they are certainly remote. In fact, we have little reason to suspect that stich organisms exist. REFERENCES Balch, R. E. 1960. The approach to biological control in forest entomology. Can. Entom. 92: 297-310. Clausen, C. P. 1951. The time factor in biological control. J. Econ. Entom. 44: 1-9. DeBach, P. 1964. The scope of biological control. In: Biological Control of Insect Pests and Weeds. DeBach, P., and E. 1. Schlinger, cds. Chapman and Hall Ltd., London. 1966. The competitive displacement and coexistence principles. Ann. Rev. Entom. 11: 183-212. Annual Reviews, Inc., Palo Alto, Calif. DeBach, P., and R. A. Sundby. 1963. Competitive displacement between ecological homologues. Hilgardia 34: 105-66. Grinnell, J. 1904. The origin and distribution of the chestnut-backed chickadee. Auk 21 : 364-82. 1917a. The niche-relationships of the California thrasher. Auk 34: 427-33. 1917b. Field tests of theories concerning distributional control. Amer. Naturalist 51: 115-28. 1924. Geography and evolution. Ecology 5: 225-9. 1928. The presence and absence of animals. Univ. California Chronicle 30: 429-50. Reprinted in: Joseph Grinnell's Philosophy of Nature. Berkeley 1943: 187-208. Huffaker, C. B., and P. S. Messinger. 1950. Population ecology-historical development. It,: Biological control of Insect Pests and Weeds. DeBach P., and E. L Schlinger, eds. Chapman and Hall Ltd., London. Lindroth, C. H. 1957. The faunal connections between Europe and North America. John Wiley & Sons, New York. Richards, O. W. 1955. Review: Andrewartha, H. G., and L. C. Birch. The Distribution and Abundance of Animals. Chicago Univ. Press, Chicago, Ill. ]. Anim. Ecol. 24: 465. Thompson, W. R. 1951. The time factor in biological control. Can. Entom. 83 : 230-40. The axiom that population stability is a product of the diversity of the environment is a virtually self-evident truth that is beguiling in its simplicity. As Richards 0(55) has said "It seems, at least to me, intuitively obvious that the bigger the complex of species involved the more likely to be damped are the amplitude of the (population) fluctuations." But he also warned "it is perhaps uncertain how far it is legitimate to apply general theories to small segments of the whole .... tt This warning is particularly apropos in the context of biological control. The numbers and kinds of plants and animals in an ecosystem are not simply a matter of chance; it is a characteristic of the ecosystem. This is not to claim that specific sites support only populations of specific structure, l'ither as to kinds or numbers of organisms present; extrcmely large variations of kinds and numbers are possihiL' on most sites. But the possible variations are not infinite; they arc limited by certain environmental elemcnts and community mechanisms, of which competitivc l'xclusion or displacement is one. The kind of species that can colonize a given site depends to large extent upon what specics arc already there, and the more species that arc present, the more difficult it becomes for an immigrant species to invade. :Most of the communities into which we introduce exotic cntomophages already possess populations nearing maximal lliYersity. This fact applies even to those agricultural lands in which species diversity has been deliberately imJlovl'rished. There is a limit to the number of kinds of primary producers permissible if such lands are to maintain their agricultural productivity. This limitation severely restricts all other forms of diversity, including particularly the diversity of secondary consumers, i.e., entomophages. Thus we are being hypocritical when we speak of diversity and stability in such environments. Our objective is neither. We are concerned not with increasing population diversity, but with maximizing a EN'fOMOLOGICAL CITED BRANCH JOURNALS PACIFIC INSECTS. A quarterly journal devoted primarily to systematics and zoogeography. Vol. 1 (1959) 505 pp.; Vol. 2 (1960) 461 pp.; and Vol. 3 (1961) 589 !lP.: $7.00 per vol. to institutions and dealers, $5.00 to individuals. Vol. 4 (1962) 996 pp.; Vol. 5 (1963) 945 pp.; Vol. 6 (1964) 770 pp.; Vol. 7 (1965) 922 pp.; Vol. 8 (1966) : $10.00 per vol. to institutions and dealers, $7.00 to individuals. JOURNAL OF MEDICAL ENTOMOLOGY. Quarterly journal devoted to all phases of medical entomology from the world standpoint, including systematics of artho]lods of potential medical or veterinary significance. Vol. 1 (1964) of 402 pages; Vol. 2 (1965) of 396 pages: Vol. 3 (1966). Subscription of $10.00 to institutions and dealers; $7.00 to individuals. Prices in Japan Y3500; Y 2500. Order either of the above from Entomology Dept., Bishop Museum, Honolulu, Hawaii 96819 U.S.A. MEETINGS The Pacific Branch met at the Hotel Utah in Salt Lake City on June 20-22, 1967. Chairman HOWARDE. DORST presided at this fifty-first meeting. J. E. SWIFT was installed as the new Chairman while R. E. RIEDER was chosen as Chairman-elect. Secretary-Treasurer W. W. ALLEN and Governing Board Representative G. E. CARMAN continued in these offices. The next meeting will be held at the Sahara Hotel in Lake Tahoe, California, June 25-27, 1968. The Eastern Branch met at the Holiday Inn in downtown Baltimore, Maryland on October 30 and 31, 1967, with Chairman C. K. DORSEYpresiding. R. W. SHERMAN was installed as Chairman for 1968 and R. E. Heal was selected as Chairman-elect. Secretary-Treasurer J. PETER JOHNSONcontinued in that office. The next meeting of the Eastern Branch will be in the Benjamin Franklin Hotel in Philadelphia, Pennsylvania October 31-November I, 1968. 337