OF WASHINGTON. 263 



In connection with Adler's views as to oviposition, he concludes 

 from his own studies that the main purpose of the stalk is, by its 

 posterior end remaining at the surface of the puncture, to supply 

 oxygen to the egg-body in the plant tissues ; but that this is also 

 an erroneous conclusion is, I think, made manifest by some of 

 the facts just stated. That the function of the egg-stalk is, rather, 

 to facilitate the otherwise difficult mechanical operation of the 

 passage of the egg down a narrow and elongate ovipositor in the 

 manner indicated by Hartig is supported by the fact that the 

 puncture is often closed at its mouth, as also from what we know 

 of the similar oviposition in other orders of insects. The facts, 

 for instance, connected with the oviposition of Pronuba yucca- 

 sella, where the egg is thrust deep into the ovarian cavity of the 

 Yucca pistil, bear out this view. The egg, in this' case, as it 

 passes down the ovarium has not a definite pedicel or stalk, but 

 becomes a mere thread in passing through the ovipositor (the 

 nature of which precludes any external outlet during the passage) , 

 and the fluids gradually concentrate in the apical or anterior end 

 as the embryo develops. Moreover, it is passed into the ovarian 

 cavity of the pistil and has no connection through the pedicel 

 with the exterior wound, which is closed before the larva hatches. 



The paper was briefly discussed by Messrs. Marlatt, Ashmead, 

 and Benton. Mr. Marlatt said that the mere fact that observa 

 tions on this point are so difficult is sufficient in itself to explain 

 any discrepancies. Mr. Ashmead expressed himself as inclined 

 to accept the observations of Dr. Riley. In referring to dimor 

 phism, he said that he was satisfied that the wingless species of the 

 genera Acraspis and Biorhiza are agamic forms of some winged 

 bisexual forms. He thinks, for instance, that there is a connec 

 tion between Dryophanta and Acraspis. In Florida the winged 

 bisexual form of Belonocnemus occurs on the roots of live oak, 

 the agamic form appearing on the leaves in the fall. 



Mr. Marlatt read the following paper : 



THE HIBERNATION OF NEMATIDS, AND ITS BEARING ON 

 INQUILINOUS SPECIES. 



During the summer and fall of 1894 large quantities of saw-fly 

 galls on willow were collected for me by Mr. E. L. Horton, of 

 East Steamburg, N. Y. These belong to both of the genera 

 of Nematinse (Euura and Pontania), the larvas of which develop 

 in galls on twigs or on leaves of willow. The experience 



