352 J. T. PATTERSON. 







almost without exception degenerating individuals were found. 

 During the early period of the free larval stage, any given lot will 

 show great variation in the size of the larvae. To show this, all 

 of the individuals of three lots have been measured in the terms 

 of lines on the eye-piece micrometer scale (Table II.). In Lot I. 

 there were only thirty-two larvae. All but six of these would 

 have reached maturity. Lot II. contained 176 larvae, but at 

 least twenty of these were degenerating. Lot III. contained 

 257 larvae, and probably more than a hundred of them would have 

 degenerated eventually. 



A series of sketches of these larvae is shown in Fig. 25, A to H. 

 The first four or five of these types would have developed to 

 maturity, but such larvae as those illustrated in F to H degenerate. 

 The most common types of degenerating embryos are the small 

 spherical or oval-shaped masses (G, H). In one extreme case 

 the lot of embryos consisted of about thirty of these masses, 

 together with only a single normal larva. Doubtless many other 

 similar masses had already degenerated. 



It is difficult to assign any definite cause to the degeneration 

 of these embryos, although it probably has something to do with 

 nutrition. In some cases it seems to be due to the fact that the 

 division of the egg has been carried too far. Some of the pri- 

 mordia receive but few embryonic nuclei, and these are invariably 

 the first to degenerate in the polygerm. In other cases the 

 degeneration is apparently due to the lack of proper nutrition. 

 Most of the polygerms are early surrounded by the thick layer 

 of adipose tissue, upon which the early development of the 

 embryos depends. But other polygerms are almost if not entirely 

 barren of adipose cells, and it is an observed fact that the mor- 

 tality of embryos in such cases is exceedingly high. In Fig. 14 

 one of these cases is shown. This polygerm, which is devoid of 

 fat tissue, contains more than a hundred embryos, not more than 

 thirty or thirty-five of which have developed normally. 



V. NUMBER AND SEX OF COPIDOSOMA PARASITES FOUND IN 



GNORIMOSCHEMA. 



The number of matured parasites developing in the Gnorimo- 

 schema larva has been determined in 162 cases. This has been 



