OF THE STATE ENTOMOLOGIST. 131 



THE STING, 



As already stated, is caused by the prick of the spines, and not by 

 their getting broken in the flesh. From the fact that the spines 

 appear hollow, one would naturallj'- attribute their irritating power to 

 some poisonous fluid which they eject into the puncture. But I have 

 been unable to resolve any apical aperture, nor was Mr. Lintner more 

 successful. Hence I infer that the irritating property belongs to the 

 substance of which the spines are formed, and this opinion is strength- 

 ened by the fact that those of a dead larva, or of a cast-ofl" skin which 

 has been in my cabinet for several years, still retain the irritating 

 power, though so brittle that it is not easy to insert them. All the 

 spines have the same power, though the rust-colored, fasciculate ones 

 along the back, being more acute and stouter, sting most readily ; 

 the aculei from the others being more fragile. The power is probably 

 possessed from the time of birth, though the bristles in the first stage 

 are too flexile to penetrate anything but the most delicate substance. 

 In the second stage the sting is readily produced on the more tender 

 portions of the body;* but until the rust-colored bunches of short 

 porcupine-like spines appear on the back, in the fifth and sixth stages, 

 the larva may be handled with impunity, and will hardly sting, unless 

 the spines are pressed upon the more tender skin. Even when full 

 grown, it may, with a little care, be handled without injury. The 

 eifect of the sting is a reddening of the punctured parts, and the early 

 appearance of raised whitish blotches. These are replaced by purplish 

 spots, which do not disappear for several days. 



THE PUPA. 



The larva, to transform, almost always enters the ground, and 

 there, in a simple, ovoid cell, the prickly skin is shed, and the pupa 

 state, outlined at figure 62, 2», assumed. It is now of a deep brown- 

 black color, heavy and rounded anteriorly, minutely shagreened or 

 roughened, except at the sutures of legs and wing-sheaths, where it is 

 smooth and polished. The margins of the three abdominal sutures 

 next the thorax, and of that* between the last two stigmata-bearing 

 joints, are more or less crimped or plaited, while the three which in- 

 tervene, and which are the only ones movable, are deep and trans- 

 versely aciculate (as if scratched with the point of a needle) on the 

 hind, and longitudinally and minutely striated on the front side. 

 The body ends in a triangular, flattened, ventrally concave tubercle, 

 tipped with a few curled, blunt, rufous bristles. 



*Mr. Liutner, in the paper already cited, only noticed the stinging properties after the third 

 aiiolt or in the fourth stage, and asserts that ' 'the ability to inflict a sting does not belong to all the 

 spines of the larva, but only to those of the two subdorsal rows on segments three to ten, and the 

 ■dorsal spine on segment eleven.' ' This is, however, quite incorrect, so far as my experience goes. 



