8 5 2 



Journal of Agricultural Research 



Vol. VI, No. 28 



trackeli: Cocoon, 

 enlarged. 



THE COCOON 



The cocoon of T. conotracheli (fig. 1) is about 5 mm. long by about 

 half as thick and oval in shape. It is constructed of tough reddish- 

 brown silk. 



PUPATION AND TRANSFORMATION 



About four or five days after the construction of 

 Fig. i.—Thersiiochus c<mo- the cocoon pupation takes place. When the trans- 

 Much formation to the adult condition takes place was 

 not determined by the present writer, but according 

 to Quaintance and Jenne (8, p. 147-148) Mr. Fred Johnson found adults 

 in cocoons at Youngstown, N. Y., in 1908, as early as August 24. As 

 indicated above, the species hibernates in this condition within the 

 cocoon. 



DESCRIPTION OF THE IMMATURE STAGES 



the; egg 



The egg (fig. 2) is oblong oval in shape, somewhat larger at the cephalic 

 end, abouto.33 mm. in length by a little more than a fourth as wide» 

 and slightly curved. A magnification of 215 diam- 

 eters showed no sculpture of the chorion. 



THE LARVA Fjg. 2—Thersilochus 



conotracheli: Egg. 



First instar. — The newly hatched larva (fig. 3) Highly magnified, 

 resembles in general appearance that of Limnerium validum as figured 

 by Timberlake (9, p. 84). 



The body consists of 13 segments, including the head and the long 

 taillike caudal segment. The head is somewhat more than half as long 

 as the rest of the body exclusive of the tail, which is somewhat longer 



than the head. The head 

 is bent slightly downward 

 from the general axis of the 

 body. It is heavily chiti- 

 nized and pale brown in 

 color, considerably longer 

 than wide, and strongly 

 curved above so that the 

 mouth opening is on the underside. The mouth parts consist of the 

 heavily chitinized, acute, curved mandibles and the very delicate labrum, 

 maxillae, and labium. The exact form of the last three appendages is 

 very difficult to ascertain with exactness, but they seem to be arranged 

 about as in figure 4. The mandibles are very distinct even well within 

 the head cavity, although their place of attachment is not clear. Ap- 



Fig. 3. — Thersilochus conotracheli: Larva of first instar. Highly 

 magnified. 



