24 R- W. HEGNER. 



It is the intention of the writer to repeat these operations next 

 spring. 



1. C. Innata, Exp. 6b. An egg which was laid at 1 1 a. m. 

 on July 23, was allowed to develop for twenty-five hours and 

 then was operated on. It was preserved forty-four hours after 

 the operation. Twenty-three germ-cells instead of sixty -four 

 were found occupying the normal position in the embryo. Four 

 of these twenty-three cells were in the posterior amniotic cavity 

 while nineteen were scattered among the mesoderm cells in the 

 last two abdominal segments. This difference in number can be 

 accounted for by supposing that part of them were removed in the 

 operation. 



2. C. lunata, Exp. 6c. - - A larva hatched from an egg which 

 was laid and operated on at the same time as the egg in Exp. 6a 

 The larva was preserved at once. No germ-glands could be found 

 in the sections. Several sections broke on the knife but these 

 were from a part of the larva outside of the germ-gland region. 



3. L. decemlincata, Exps. p. 1-7. It is evident from the results 

 of these experiments that either all of the primordial germ-cells 

 were not removed from the egg during the operation or else some 

 other cells have taken on the function of germ-cells. In one case 

 (L. decemlineata, Exp. p. 2) it is certain that all the pole-cells 

 were not removed. In two instances (Exps. /. 4 and /. 6) germ- 

 glands were undoubtedly present. The method of operating 

 therefore needs to be improved before decisive results can be 

 secured. 



III. THE EFFECTS OF REMOVING OTHER PORTIONS OF THE 



EGG. 



Only one experiment was made to note the effect of removing 

 any part of the egg other than the posterior end. The anterior 

 end of a freshly laid egg of C. bigsbyana (Exp. C. b. i) was punc- 

 tured and a large drop of the contents removed. A normal larva 

 hatched from this egg, passed through the larval and pupal stages 

 and is now hibernating as an adult. 



The above experiments prove that a part of an insect's egg 

 may be removed without preventing the development of the em- 

 bryo and subsequent hatching of the larva. More work must be 



