Stinging caterpillars do not sting in the familiar manner of bees, yellowjackets, hornets, and wasps (Order Hymenoptera). In the bee-wasp group, females (only females sting) are equipped with venom glands and stingers (modified ovipositors) with which they penetrate skin and introduce venom.
www.ag.auburn.edu/enpl/bulletins/caterpillar/caterpilla... www.ag.auburn.edu/enpl/bulletins/caterpillar/caterpillar.htm
But there are a few Stinging caterpillars of various shapes, sizes and colors. Stinging caterpillars possess hollow quill-like hairs, connected to poison sacs, that are used as defensive weapons. When these hairs are touched they break through the skin releasing the poison.
www.ca.uky.edu/ENTOMOLOGY/entfacts/ef003.asp
Australian Lepidoptera (moths and butterflies) contain several species of caterpillars that are armed with stinging hairs and/or fragile spines. These modified hairs serve as an effective means of protection against predators intertested in the soft bodied caterpillars.
medent.usyd.edu.au/fact/caterpillars.htm medent.usyd.edu.au/fact/caterpillars.htm
The puss caterpillar sting is the most severe of these stinging caterpillars. Venom is discharged upon contact. ... The stiff hairs, or spines, are mildly poisonous, with the sting somewhat less painful than other stinging caterpillars. Some individuals report severe irritation nevertheless.
ohioline.osu.edu/hyg-fact/2000/2130.html
Stinging caterpillars possess hollow quill-like hairs, connected to poison sacs, that are used as defensive weapons. When these hairs are touched they break through the skin releasing the poison. Reactions can range from a mild itching to the more severe pain, dermatitis, and even intestinal disturbances.
bexar-tx.tamu.edu/IPM/Landscape/F1/nStingingCaterpillar... bexar-tx.tamu.edu/IPM/Landscape/F1/nStingingCaterpillars.htm
A. There are several stinging caterpillars in Texas, including the saddleback caterpillar, buck moth, the hag moth and the puss caterpillar, also known as wooly worm or the asp. The asp, the larva of the flannel moth, can cause severe pain, rapid swelling, shocklike syndromes, convulsions and intense itching.
www.chron.com/disp/story.mpl/life/huber/277592.html
‘Tis the season where little ones discover a world full of creepy, crawly things in the backyard and the playground.  Centipedes, inchworms, and caterpillars make great finds for anyone’s bug catcher, but know that there ... Several types of caterpillars can cause a very ugly reaction because of their stinging hairs.
www.care2.com/greenliving/stinging-caterpillars-cute-fu... www.care2.com/greenliving/stinging-caterpillars-cute-fuzzybut-itchy.html
STINGING CATERPILLARS ; By Ric Bessin ... Most encounters with stinging caterpillars result from accidentally brushing against leaves on which they are feeding. The chances of running into these insects are relatively low, but occasionally one species may be very abundant.
www.uky.edu/Ag/kpn/kpn_03/pn030818.htm
Stinging caterpillars use poison-filled bristles to defend themselves from predators. If you touch a stinging caterpillar, you'll know it by the burning, itching, or just plain painful sensation that follows. These pictures will help you learn to recognize stinging caterpillars - before you touch them. ... stinging insects...
insects.about.com/od/butterfliesmoths/ig/Stinging-Cater... insects.about.com/od/butterfliesmoths/ig/Stinging-Caterpillars/
Stinging caterpillars do not sting like bees, yellow jackets, hornets and wasps. Stinging caterpillars possess hollow quill-like hairs, called setae, connected to poison sacs. These structures are primarily used for protection from predators.
forsyth.ces.ncsu.edu/files/library/34/CES_Venomous_Cate... forsyth.ces.ncsu.edu/files/library/34/CES_Venomous_Caterpillars.pdf