THE MONTHLY BULLETIN. 



207 



'i'he color of the integument assumes a pinkish tinge. The curve of 

 the body is very strong. The body contents do not show through the 

 skin as conspicuously as in the other stages, the skin becoming more 

 opaciue. The urates are indistinct. The swollen areas on the lateral 



Fig. 67. — Full-grown lai va nf Calliephialtes 

 sp. Greatly enlarged. (Original.) 



edges are very prominent. The greatest width is transverse. The con- 

 tents of the iiost are nearly drained out and at the end of the stage 

 little remains but the skin, which is pushed to one side and end of the 

 host cocoon at the time the parasite larva starts to spin its cocoon. 

 There is much increase in the size of the head over the preceding stage, 

 the length increasing to about .55 mm., or a proportionate increase of 

 11 to 8, and the width increases to about .75 mm., or in the ratio of 15 



Fig. 68. — Larvae of Calliephialtes sp. feeding on codling 

 moth larvae. Enlarged. (Photo by Esslg. ) 



to over the fourth stage. The greatest increase in size, of course, is 

 in the body, the larva averaging for both males and females 6.9 mm. and 

 in width 2.7 mm., the males as a rule being the smaller. The females 

 average over 8. mm. and the males under 8. mm. At the temperatures 

 previously recorded the larva will spin its cocoon in from seventeen to 

 thirty days after having emerged from the egg. The larva voids the 

 meconial grains and pushes the remains of the host to one end and 

 side and proceeds to spin the cocoon. 



The Cocoon. (Figure 69.) The first process in spinning the co- 

 coon of (Jalliephialtes sp. consists of spinning a series of whitish threads 

 which form the outer network and serve to shape the cocoon. Under 

 this the larva forms the layers of the cocoon proper which are closely 

 woven and impervious to the air, or nearly so. The finished cocoon is 

 usually of a yellow brown color, thin and tissue-like and consists of 3 to 



