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Welcome to the Colorado State University Extension Western Colorado Entomology web site. This site was created and is maintained by Tri River Area Extension Entomology & Agronomy, and is dedicated to presenting factual information on the insects and insect related issues affecting western Colorado.

Native Insects   arrow

Arachnida-Spiders and Scorpions

Araneidae

Argiope trifasciata Forsskal

Banded Argiope
Colorado Insects of Interest Fact Sheet (pdf)
Banded Argiope

Photo by Whitney Cranshaw.

Araneidae

Araneus gemmoides Chamberlin and Ivie

Cat-faced Spider
(Western Plains Orb-weaver)
Colorado Insects of Interest Fact Sheet (pdf)
Cat-faced spider

Photo by Whitney Cranshaw.

Daddylonglegs
(Harvestmen, Opilionids)
Colorado Insects of Interest Fact Sheet (pdf)
Daddylonglegs

Photo by Whitney Cranshaw.

Funnel Weaver Spider
(Funnel-web weavers, Grass spiders)
Colorado Insects of Interest Fact Sheet (pdf)
Funnel Weaver Spider

Photo by Whitney Cranshaw.

Jumping SpidersColorado Insects of Interest Fact Sheet (pdf)
Jumping Spider

Photo by Whitney Cranshaw.

PseudoscorpionsColorado Insects of Interest Fact Sheet (pdf)
Pseudoscorpion

Photo by Whitney Cranshaw.

Dysderidae

Dysdera crocata Drury

Roly-poly Killer
Woodlouse Hunter
This smooth bodied spider is perhaps best distinguished by its large fangs which it uses to feed on pillbugs (roly-polies) and other hard-bodied prey. When full grown they are about .5 inch in length. Dysdera have a generally creamy gray body with distinctly reddish legs and cephalothorax. They live in a silk retreat and hunt at night. Their bite can be painful but they are not aggressive and their venom is not known to cause medical problems.

Colorado Insects of Interest Fact Sheet (pdf)
Roly-poly Killer spider.

Photo by Whitney Cranshaw.

ScorpionsColorado Insects of Interest Fact Sheet (pdf)
Scorpion.

Photo by Bob Hammon.

Theraphosidae

Aphonopelma spp.

Taranchulas
Colorado Insects of Interest Fact Sheet (pdf)
Female tarantula.

Photo by Whitney Cranshaw.

Lycosidae

Wolf Spiders
These spiders are sometimes mistaken for Nursery Web spiders. These spiders are good hunters often chasing their pray over a short distance. The female lays an egg sac then attaches it to the underside of her abdomen to protect it. Once the eggs hatch the new spiderlings are carried around on the females back
Wolf Spider with spiderlings.

Photo by Bob Hammon.

Eutichuridae

Cheiracanthium inclusum (Hentz), C. mildei C.L. Koch

Yellow-legged Sac Spider
Colorado Insects of Interest Fact Sheet (pdf)
Yellow-legged Sac Spider

Photo by Whitney Cranshaw.