48 
Poisonous Arthropods 
slender chitinous hair whose tip is readily broken off in the skin and 
whose poisonous content causes great irritation. Some individuals 
are very susceptible to the poison, while others are able to handle 
the larvae freely without any discomfort. The larvae feed on a wide 
range of food plants. They are most commonly encountered on 
coni and on willow, because of the opportunities for coming in contact 
with them. 
The larvae of the brown-tail moth (Euproctis chrysorrlioea,) (fig. 
35 and 36), where they occur in this country, are, on account of their 
great numbers, the most serious of all poisonous caterpillars. It is 
35. Larva of brown-tail moth. (Natural size). Photograph by M. V. S. 
not necessary here, to go into details regarding the introduction of 
this species from Europe into the New England States. This is all 
available in the literature from the United States Bureau of Entomol¬ 
ogy and from that of the various states which are fighting the species. 
Suffice to say, there is every prospect that the pest will continue to 
spread throughout the Eastern United States and Canada and that 
wherever it goes it will prove a direct pest to man as well as to his 
plants. 
Very soon after the introduction of the species there occurred in 
the region where it had gained a foothold, a mysterious dermatitis of 
man. The breaking out which usually occurred on the neck or other 
exposed part of the body was always accompanied by an intense 
