248 TRANSACTIONS OF THE ILLINOIS 



numerous little rings, of which I find about six to the segment. They 

 are covered everywhere with fine short whitish hairs; interspersed among 

 these are minute black conical tubercles or elevated points. By examin- 

 ing closely with a pocket magnifier it will be seen that these black points 

 are arranged in rows along the transverse ridges into which the segments, 

 as before stated, are divided, the intervening transverse impressed lines 

 being smooth and without hairs or tubercles. The head is rather small 

 and is also hairy ; the body tapers very slightly towards each extremity ; 

 there are six true legs — eight abdominal and two anal fleshy prolegs. The 

 general color, which is nearly uniform throughout, is often described as 

 pea-green. While this is sufficiently correct for general purposes, yet if 

 we examine them closely we find the green has a slightly bluish cast, 

 more apparent on the under side, which is paler than the dorsal surface. 

 There is usually a narrow yellow line along the middle of the back, but 

 this is sometimes partly obliterated, and one now (Nov. 24) before me 

 and alive shows scarcely any sign of it, a mere trace being visible on the 

 first and second segments, and this so faint as to be seen only with a glass 

 under certain reflection of light. On each side near the lower margin 

 there is a row of bright yellow dots, one on each segment a little behind 

 the stomata or breathing pore. 



When young their skin is somewhat glossy and shining, but when 

 they reach maturity the surface assumes a velvety appearance, given it by 

 the numerous minute pimples and short hairs with which it is covered. 



The following descriptions by others are introduced here for the 

 purpose of enabling examiners hereafter to determine questions as to 

 local varieties. 



Curtis, in his "Fartn Insects,^'' briefly describes it as follows: 



The eggs are not unlike those of F. brassiccB in form and sculpture, but the cater- 

 pillars are totally different, being green, and so densely covered with minute hairs as to 

 be velvety. They have a yellowish stripe down the back and another along each side, 

 the venter being of a pale, brighter green; they are often more than an inch long, and 

 about as thick as a crow quill. 



His figure shows distinctly the lateral stripe. 



Goreau's description, in his ^'Insectes Nuisibles,'" is evidently copied 

 entire from Curtis. 



Boisduval, in ^^Entomologie Horticole^^^ describes it very briefly, but 

 mentions three longitudinal yellow lines, one along the back and one 

 along each side just above the feet. 



Stephens, in '■^British Entomology,'''' describes the caterpillar as 

 "green, with a pale line on the back, and a whitish line, often punctured 

 with yellow, on each side." 



But the most complete description is that given by Dr. Fitch in his 

 Thirteenth Report, as follows: 



When examined with a magnifying glass, the surface of these worms is found to be 

 everywhere bearded with fine, short, whitish hairs, those upon the back shorter, and 

 the young worms black and interspersed with small stiff bristles. These hairs arise 

 from numerous minute, black, elevated points, with which the surface is everywhere 



