1. Arachnids
Section 30.2

2. Features of Arachnids Spiders, scorpions, ticks, mites, daddy longlegs
Cephalothorax and abdomen
No antennae
1st pair of appendages are chelicerae – modified into pincers or fangs
2nd pair of appendages are pedipalps – modified to catch and handle prey
No jaws  inject prey with poison to liquefy it

3. Spider fangs

4. Some arachnids have pincers

5. Spiders Chelicerae modified into fangs
Poison glands secret toxin through the fangs that paralyzes or kills the prey
Only two U.S. spiders are dangerous: black widow and brown recluse
Strands of silk are produced in the spinnerets in the abdomen

6. Black Widow spider

7. Brown Recluse Spider

8. Brown Recluse Spider bite

9. Webs are made from silk produced in spinnerets

10. Computer enhanced photo of spider spinnerets

11. Scorpions and Mites Scorpions – stinger on the end of the abdomen
Pedipalps are pincers
Mites – largest group of arachnids
Head, thorax and abdomen are fused into unsegmented body
Some are plant or animal parasites (ticks)

12. Scorpion

13. House dust mite

14. Deer ticks – can carry Lyme disease