36 JOURNAL OF THE [January, 



advantage to the larva now, and that they serve as a powerful 

 means of defense. Of course the little creature does not shoot 

 off its arrows, like a bowman of mediaeval times, or, as according 

 to popular belief, the porcupine shoots off its quills, but, like the 

 spines of hedgehog and porcupine, these peculiar hairs protect 

 the otherwise defenseless creature by presenting a formidable 

 array of sharp points to the voracious foe. This larva of Atia- 

 genus, living as it does under the bark of decaying trees, in old 

 skins, carpets, boxes, butterfly-collections, etc., is not so much 

 exposed to the danger of being eaten up by birds as by other 

 and bigger larvae, centipedes, ants, &c., and against these the 

 hairs, in my opinion, are an efficient protection. The arrow- 

 heads, being much finer pointed than the finest needle will pierce 

 any skin or substance, not absolutely hard, the very instant 

 they are touched. Being barbed in a very elaborate manner 

 and only attached to the shield by a thin and brittle neck, they 

 break off and remain in the skin, causing no doubt acute pain. 

 I have observed many of these larv^ and have found that they 

 can be handled with impunity, owing to the thickness of the 

 skin of our fingers, but the moment I rubbed them against my 

 lips I felt a burning sensation, almost like that caused by a 

 nettle-leaf, which would last for several minutes. From the 

 apex of the arrow-head, down through the entire length of the 

 hair a tube or canal extends (distinctly visible even with a half- 

 inch objective) and this, there can be no doubt whatever, is 

 filled with a poisonous or acid substance, which causes what to 

 us is a slight inflammation, but what may be agony and death to 

 little insect enemies. 



That the heads can be easily detached from the hair is a 

 fact which may be verified by experiment at any moment, and 

 that they are intended to break off and torment attacking 

 enemies is extremely probable. I am also perfectly convinced 

 that the hairs, when deprived of their " heads," are not only 

 capable of reproducing the latter, but that they invariably do so, 

 as long as they remain attached to the skin of the living insect. 

 When the head is gone the " shield " is modified into a new 

 head and the next link or division of the stem into a shield, and 

 this process may be repeated a dozen times if necessary. The 

 funnel-shaped spiny whorls are merely incipient heads, each 

 intended to take the place of the one preceding it, if the 

 contingency arises. 



