98 NEW YORK STATE MUSEUM 



may be observed five days before they escape. The embryos 

 are inclosed in the amniotic sac, which latter is ruptured before 

 they escape from the body of the mother larva. There is a marked 

 tendency among the embryos, when more than one occurs, to de- 

 velop with their heads toward both extremities of the mother larva. 



The growth of the embryo is correlated, as alluded to above, by 

 interesting modifications in the mother larva. The large, well 

 developed mother larva is easily recognized by her plump condition 

 and the nearly solid, submedian masses of white adipose tissue filling 

 the body from the fifth or sixth segment to the posterior extremity. 

 Shortly after the escape of the embryos from the ovaries we observe 

 clear patches (pi. 23, fig. i), here and there in the mother larva, 

 bordered by cells well filled with adipose tissue. Within a few days 

 there is a striking modification and these large cells lose, probably 

 by osmosis, a large proportion of the white, fatty matter and 

 assume a somewhat reticulate character (pi. 23, fig. 2), which is 

 soon followed by their disappearance, and the embryos absorbing 

 practically all of the contents of the mother larva. 



Records of individual embryos. The embryo in larva A was 

 first detected January 17th. It then had a length about equal to 

 two and one-half body segments of the mother larva. There was 

 a distinct median streak of large, irregular cells, with a broad pro- 

 jection to one side near the anterior third, and a distinct cephalic 

 cap of dark cells at the anterior extremity (pi. 32, fig. i). The next 

 day the germinal strip occupied an area approximately equal to 

 one-third the width of the embryo (pi. 32, fig. 2), extending the 

 following day to about half the width of the embryo, the clear 

 space just behind the cephalic extremity being decidedly smaller. 

 At this time the embryo had increased in length so that it extended 

 from the posterior third of the fifth to the anterior fourth of the 

 eighth body segment of the mother larva. There was some in- 

 crease in length and minor changes in development from that date 

 to the 27th, at which time there was a remarkable change, the 

 germinal streak and its production to one side becoming narrower 

 and being composed of unusually large cells ; this change was soon 

 followed by disintegration, the condition on the 28th being well 

 illustrated on plate 32, figure 3. 



The embryo of larva B was recognized January 17th, at which 

 time it extended from the fourth body segment of the mother 

 larva to the twelfth. The greater portion of the embryo consisted 

 of a nearly uniform series of small, globular cells, though a darker 

 area was visible on one side near the middle (pi. 34, fig. i). Pulsa- 



