DEVELOPMENT OF COPIDOSOMA GELECHI^. 347 



from the adipose layer invade the inter-embryonal spaces. The 

 fat cells are the last elements to enter the inter-embryonal sub- 

 stance. In Fig. 13 a wedge-shaped mass of fat tissue is seen 

 lying between the embryos in the middle region of the polygerm, 

 on the upper side. Perhaps it would be more correct to say that 

 the embryos bud out into the adipose tissue. Thus in Fig. 24 

 a single primary mass has been budded off into the adipose tissue. 

 The final condition of the polygerm at the end of the formation 

 of the inter-embryonal substance is shown in Fig. 16. The 

 adipose tissue has invaded the inter-embryonal substance from 

 all sides of the polygerm and has become an organic part of this 

 substance. The fat body and the included polygerm become 

 an extremely complex structure, which may be called the poly- 

 germal mass. 



2. Dissociation of the Polygermal Mass. 



The setting free of the larval parasites into the body cavity 

 of the host is brought about through the dissociation or disin- 

 tegration of the inter-embryonal substance. The fat brought 

 into close contact with the embryos by the invasion of the adipose 

 tissue is digested and absorbed by them. It is therefore the first 

 component of the inter-embryonal substance to disappear. 

 That the fat is digested and consumed by the embryos is evi- 

 denced by the fact that the numerous other fat bodies remain 

 intact during this period. The disappearance of the fat leaves 

 the embryos loosely held together by the plasmalike matrix, 

 which in turn soon disintegrates, freeing the larvae. 



The first larvae to be set free are those situated at the periphery 

 of the polygermal mass. Such larvae are usually the largest 

 present in the mass. As the inter-embryonal substance slowly 

 disintegrates the remainder of the larvae are gradually set free 

 (Fig. 17). The earliest date at which free larvae have been found 

 was July 19; the latest, July 31. In the vast majority of cases 

 the mass dissociates during the last week of July. 



The larvae retain the involucres for some time after being set 

 free (Fig. 18). Once free in the body cavity they proceed to 

 devour the contents of the host, first consuming the fat tissue, 

 and finally the various organs. The last internal organ to dis- 

 appear is the intestine. 



