32 J. T. PATTERSON 



It may take place as early as the fourth day, or it may be delayed 

 until the eleventh day. Indeed, in some few eases the polygerm 

 does not completely break up until the larvae are on the point of 

 being set free. The fragmentation is largely controlled by the 

 relation of the polygerm to the host tissue. If it lies free in the 

 body cavity or in loose tissue, dissociation will occur very early; 

 but if it is embedded in rather dense tissue, such as the ganglion 

 or fat, the dispersal of the embryonic masses maj^ be greatly 

 delayed. 



The primary masses are organized toward the end of the third 

 day (figs. 52, 53), and are completed during the early part of 

 the fourth day. If the young polygerm of this period happens 

 to be free from host tissue, the separation of the primary masses 

 may set in. Figure 53 is a polygerm seventy-seven hours old, 

 and signs of breaking up are apparent. The asexual embryo has 

 already become completely separated from the other primary 

 masses. In the same preparation there are several polygerms 

 from which one or more primary masses have broken away and 

 lie some distance from the main body of the polygerm. 



The usual time for dissociation to occur is during the period 

 in which secondary and tertiary masses are being formed, that 

 is, from the end of the fourt'i to about the tenth day. Figure 

 69 is a ganglion containing a polygerm ninety-five and one-half 

 hours old. The secondary masses are beginning to dissociate. 



Figure 73 is a polygerm ninety-five hours old and composed of 

 secondary and tertiary masses. It is undergoing dissociation. 

 The adipose tissue has nearly all been absorbed and the embry- 

 onic masses are beginning to scatter. 



Figures 74 and 75 are portions of the same polygerm, showing 

 groups of asexual embryos and tertiary masses, respectively. 

 The polygerm is nine days and twenty- three hours old. A large 

 number of tertiary components are found in the body cavity of 

 the caterpillar, scattered throughout its entire extent. 



If bound together by nervous or fat tissue, the embryonic 

 masses may remain connected until the eleventh day or even 

 later. Figure 71 is a ganglion containing a seven-day polygerm, 

 which shows no signs of fragmentation. The polygerm shown 



