04. [January, 



tlie larva which has emerged on the dorsum. All these ahove-mentioned 

 larvae were late in emerging. At tv, is the loose outer web of those 

 larvae which had emerged sooner and which are now nearly hidden. 



In several cases immediately after the parasite had emerged, I 

 removed it from the surface of the body of its host and placed it on a 

 glass plate ; nevertheless it began at once to spin its cocoon. Disturbed 

 and shifted several times, the parasite will at each time patiently begin 

 again to spin its cocoon. It is extremely rare, however, to find any larvae 

 further than half an inch from the body of the host. The spinning of 

 the coconn seems to follow as a reflex after the emergence of the larva 

 from the carcase of the caterpillar. 



On the Condition op the Body of the Host Cateepillar 

 AFTER Emergence of the Parasitic Lartae. 



Those who have had occasion to open the body of a Lepidopterous 

 larva containing one or more Tachinid larval parasites must have been 

 surprised at the complete manner in which the adult caterpillar's body 

 has been cleared out of all but necessary organs. In cases I have 

 examined hardly a vestige remains of the fat-body. On the analogy of 

 Tachinid parasitism one might expect to find the same to appl.y to the 

 adult Pierine caterpillar parasitized by Apanteles larvae, which also in 

 the last third of their larval life consume the fatty tissues of their host. 

 I have cut sections of the parasitized caterpillar before and after the 

 exit, and find that, as one would expect, the condition of the fat-body 

 depends on the number of parasites in the host. In all cases, however, 

 thin sheets of fatty tissue remain after the exit of the larvae ; but when 

 only a few parasites are in the body of the caterpillar, the fat-body may 

 be rather extensive. In such cases the caterpillar may arrive at the 

 pupal stage. I have met no case in which such an individual gave rise 

 to an imago, but I believe this has occurred, and has been reported. 



In my sections of the caterpillar after exit of the larvae, the holes 

 in the body are found to appear as gaps, or complete breaks in the 

 section of tlie body-wall. 



In the several cases examined, I found that caterpillars killed some 

 days after emergence of the bulk of the parasites contained one or more 

 which did not emerge with the others. Whether these Avere alive, or 

 why they did not emerge with their fellows, I do not know. 



In both Tachinid and Braconid parasitism the size of the gonads is 

 nearly always seriously affected, and such individuals have no sperma- 

 tozoa developed, as have the unparasitized Pierine caterpillars. In no 



