THE STATE ENTOMOLOGIST. 123 



the head and anal plate have a soft bluish velvety appearance, and 

 the hairs seem more dense. After undergoing a fourth moult with- 

 out material change in appearance, they acquire their full growth in 

 about six weeks from the time of first feeding. At this time they ap- 

 pear as at Figure 53, and for those who are interested in such mat- 

 ters, I quote below Dr. Fitch's description of the full-grown larva, as it 

 is the first accurate and detailed description that was published, and 

 as I have occasion to refer to it further on : 



"The caterpillar, as seen after it has forsaken its nest and is wandering about, is an-i 

 inch and a half long and 0.20 thick. It is cylindrical and of a pale blue color, tinged low 

 down on each side with greenish gray, and is everywhere sprinkled over with black points and dots. 

 Along its back is a row of ten or eleven oval or diamond-shaped white spots which are similarly 

 sprinkled with black points and dots, and are placed one on the fore part of each segment. Behind 

 each of these spots, is a much smaller white spot, occupying the middle of each segment. The 

 intervening space is black, which color also forms a border surrounding each of the spots, and on 

 each side is an elevated black dot from which arises usually four long black hairs. The hind part 

 of each segment is occupied by three crinkled and more or less interrupted pale orange-yellow 

 lines, which are edged with black. And on each side is a continuous and somewhat broader stripe 

 of the same yellow color, similarly edged on each of its sides with black. Lower down upon each 

 side is a paler yellow or cream-colored stripe, the edges of which are more jagged and irregular 

 than those of the one above it, and this stripe also is bordered with black, broadly and unevenly on 

 its upper side and very narrowly on its lower side. The back is clothed with numerous fine fox- 

 colored hairs, and low down on each side are numerous coarser whitish ones. On the under side is 

 a large oval black spot on each segment except the anterior ones. The legs and prolegs are black 

 and clothed with short whitish hairs. The head is of a dark bluish color freckled with numerous 

 black dots and clothed with short blackish and fox-colored hairs. The second segment* or neck is 

 edged anteriorly with cream white, which color is more broad upon the sides. The third and fourth 

 segments have each a large black spot on each side. The instant it is immersed in spirits the blue 

 color of this caterpillar vanishes and it becomes black. 



At this stage of its growth the Tent-caterpillar of the Forest may 

 be seen wandering singly over different trees, along roads, on the tops 

 offences, etc., in search of a suitable place to form its cocoon. It 

 usually contents itself with folding a leaf or drawing several together 



» It is necessary to remark here that in the above description, Dr. Fitch reckons the head as 

 the first segment and the first leg-bearing segment of the body, which he calls the neck, as the sec- 

 ond segment. If Lepidopterists could be induced to adopt some uniform rule in describing larva, 

 it would prevent much confusion and error. 



It is astonishing how loosely these segments are referred to by most authors. Thus Dr. Fitch, 

 after calling the head the first segment in the above description, excludes it in the descriptions of 

 the larva? of Dryocampa senatoria and Dryocampa stigma which immediately follow (Reports 3, 4 

 and 5, % 322 and 323), and speaks of the long anterior horns as proceeding from the second seg- 

 ment, whereas, to be consistent, he should have made them proceed from the third segment, as Mr. 

 Wm. Saunders has done with Dryocampa rubicunda {Can. Entomologist II, p. 76). Dr. Packard 

 (Guide etc, p. 271) speaks of the caudal horn of the larvae of Sphingidce as proceeding from the last 

 segment, which it certainly does not, whichever custom be adopted. Westwood (Intr., II,) though 

 his language on page 319 would lead one to suppose that he included the head as the first segment, 

 more often adopts the other rule, as for instance when he refers to the 11th segment in Mamestra, 

 etc., (p. 344). Burmeister in his Manual of Entomology evidently excluded the head as a segment, 

 for he refers (p. 35) to the " three first segments of the body following the head," and afterwards 

 (p. 41) speaks in more precise terms of the body consisting of 12 segments. 



Strictly speaking, the normal insect larva is composed of 13 segments, and a more or less dis- 

 tinct terminal sub-segment ; but in all those larva; in which the anterior segment is covered by a 

 horny case, so as to form a distinct head, it seems more appropriate to consider this as the head in 

 contradistinction to the twelve articulations of the body. Especially is this the case with Lepidopte- 

 rous larvsB, which are so plainly marked with a horny head, 12 soft joints and a terminal sub- 

 joint; and this plan has been adopted by most of the leading entomologists, including Boisduval, 

 Guenee, Harris, etc. 



In my own descriptions I have always adopted this course, so that when I speak of the first 

 joint I mean that immediately following the head. Of late I have adopted the term joint because 

 it is shorter and perhaps more strictly accurate than segment. I also discard the termfeet, as often, 

 applied to the horny articulate legs, for they are not feet in any sense of the word, but are the 

 true legs of the insect, and the simple term legs or thoracic legs will at once distinguish them from 

 the abdominal an anal prolegs or false legs. 



