98 THE BUTTERFLIES OF NEW ENGLAND. 



a very thin and delicate septum composed of two layers ; this membrane never 

 entirely separates the egg cell from the nutritive cells, but leaves a small 

 hole through which projects a process of the egg cell for the purpose of 

 obtaining food from the nutritive cells ; it is known as the nutritive pro- 

 cess (63 : 2 np). 



Over the whole outside of the ovariole there is a very distinct firm 

 membrane, the tunica propria (63:1, 2tp), which is produced by the 

 epithelium as a sort of cuticle. Outside of this the peritoneal membrane 

 may be seen (63 : 1 p) ; it is of mesodermic origin. In the stage repre- 

 sented in fio". 2 the epithelial cells have become flattened laterally and 

 arranged themselves in rows corresponding to the future ribs of the egg 

 shell which is produced by them. 



Though the butterfly emerges in the autumn, the eggs are not deposited 

 until quite late in the following spring, so it will be seen that the develop- 

 ment is comparatively slow. The large number and the simultaneous 

 development may account for it. I had the good fortune to observe the 

 insect in the act of oviposition. It was about noon of a sultry day, which 

 had become quite cloudy and was threatening rain. Along the side of 

 the road some wnllows had grown up like shrubs, perhaps six feet high ; 

 on one of the upper stems I noticed the butterfly standing on the stem 

 with her wings closed back to back ; she allowed me to approach till my 

 head was within two feet of her. She moved her abdomen from side to 

 side depositing the eggs in a row at the rate of about five or six a minute ; 

 now and then she would move forward in order to accommodate the length 

 of her abdomen to the point where she was depositing. I watched her 

 while she was laying perhaps one-third of the mass ; at first she seemed 

 to pay no attention to me although I was so close, but finally, probably on 

 account of my moving, she seemed to become restless, laid quite a num- 

 ber of eggs on top of the others, and then without warning was ofi". I 

 cut the stem at once and noticed on the mass of eggs a little Hymenop- 

 terous parasite* which seemed to be depositing eggs also. It would run 

 across the egg mass, then pause a moment or two over two or three eggs 

 in succession, and then be off to another part of the egg mass and repeat 

 the performance. The specimen was preserved and some of the eggs 

 allowed to hatch but no trace of parasitism appeared in them. The stem 

 on which this egg mass was laid is almost a quarter of an inch in diameter 

 and the mass covers at least half inch in length, and is the largest mass 

 laid by this species of which I have ever heard. 



The egg, as already remarked, is apparently without a nucleus and it 

 suggests the question : What is the function of the nucleus ? Is it 

 the motor power that impels the cell to the exercise of its functions ? If 

 such, it would seem that the nucleus had indued the protoplasm with such 



* This has been determined by Mr. Howard as Telenomus graptae (89 : 9). 



