EGGS AND CATERPILLARS 15 



granulated, or hairy, or have tubercles or warts froni 

 which grow stiff spines or bristles. In a few instances 

 the hairs or spines are charged with a poisonous fluid 

 secreted by glands at their base, and affect one's hands 

 as nettles do on slight contact. The effect is short- 

 lived, however, and leaves no ill result. The spines of 

 Hijperclur'ia i'o and the hairs of Lago'a crispa'ta have 

 this nettling or urticating power, and the caterpillars 

 should be handled with care.^ 



Some caterpillars have little sacs, like pockets, which 

 they turn inside out with a jerk when disturbed. The 

 sacs are filled with a fluid which is in some way un- 

 pleasant to birds and other enemies, and serves to 

 protect the larva from them, as it is thrown out by the 

 jerking of the sac. Others protrude fine threads or 

 filaments which discharge a defensive fluid, which may 

 or may not have an odor perceptible to us. 



The caterpillar stage is usually a little more than 

 five weeks for species which pass the winter as pupae 

 or in the Qgg. Those which hibernate as larvae have 

 a much longer caterpillar life, though most of it is in- 

 active. The Cos'sid(S, or boring caterpillars, which 

 live inside the wood of trees, have still longer lives, 

 some of them having a larva stage of three years, it is 

 thought. We have had broods most of which fed for 

 a month, then pupated, while one or two of the cater- 

 pillars fed for a week or two longer, and we had one 

 brood of cynthia the greater number of which fed for 

 thirty-seven days, while fifteen or twenty fed for one 



1 The hairs of the larvte of the "brown-tailed moth," now established 

 in eastern Massachusetts, cause more lasting discomfort than those of 

 any of our native caterpillars. 



