Download two pair of legs

Arthropoda Practice
Chapter 24
Class Arachnida
• Ticks, mites, scorpions, and spiders
• No antennae
• Two body regions: cephalothorax and abdomen
• Feeding appendages are chelicerae Most are carnivorous
• They hold the prey with chelicerae, and pour enzyme-rich salivary juices over the victim
• Digestion is mostly external
• Most are terrestrial
• Black widow females tend to eat males after mating because males can only mate once
and then die. It ensures the success of the offspring.
Class Crustacea
• Lobsters, crayfish, shrimp, and others
• Primarily aquatic
• Free-floating larval stage
• Branched appendages:
Class Chilopoda
• Centi means hundred, pede means legs
• 1 pair of legs per segment
• Usually shiny, reddish brown, less than 3 inches long
• Move rapidly, often found under logs; some in homes
• Can bite
• have poison claws- modified 1st pair of legs
• supposedly feels like a bee sting
• South American centipedes can be up to 1 ft in length
with a painful and agonizing bite!
Class Diplopoda
• Millipedes milli means thousand, pede means legs
• Most feed on decaying matter
• Diplo means two, poda means feet, so two pair of legs per segment
• Generally harmless detritus feeders
• Some species can eject cyanide (poison), so be careful if traveling to
South America
Merostomata
• Horseshoe Crabs
• Blue blood due to copper
• Used to detect bacteria
• Used to kill bacteria resistant to antibiotics
• Study the eyes for insight into human eyes
Class Insecta
• The insects are the most numerous and diverse of all the groups of
arthropods.
• Three body regions: head, thorax, abdomen
• Three pairs of legs
• One pair of antenna
• Many have wings