Biology Chapter 20: Section 20.3

spiders and daddy longlegs, mites and ticks, and scorpions (small, insect-like arthropods) (eight legs)

arachnids

how many distinct regions of the body do spiders have?

2

a fused head and thorax

cephalothorax

what kind of eyes do spiders have?

simple eyes

a pair of short appendages; either of two special front legs of a spider that often function as fangs.

chelicerae

spiders that attack only when they are hurt or frightened

black widow, brown recluse, and red widow

have fangs that point inward and move in and out, crossing in the middle

true spiders

have fangs that point down and move up and down

tarantulas

designed for sucking liquids

spider mouth

an appendage that looks like a small leg, is attached to each side of a spider’s mouth

pedipalp

helps the spider cling to walls and ceilings

scopular

the organs that the spider uses to spin silk

spinnerets

hatch inside the silken cocoon and remain inside until the arrival of warm weather

spiderlings

longest-lived of all spiders

tarantulas

(harvestmen) a group of arachnids famous for their long, spindly legs

daddy longlegs

found in most temperate climates and in all tropical climates (can be ovoviviparous and viviparous); has a stinger

scorpions

make up an order of tiny blood-sucking arachnids that parasitize both man and animals

mites and ticks

caterpillar-like creatures

centipedes and millipedes

flattened body, a pair of long, jointed antennae, venomous, a single pair of legs attached to each of its body segments

centipedes

rounded bodies, shorter antennae, harmless, have two pairs of legs per segment

millipedes