OF WASHINGTON. 255 



species in different Orders, especially. in the Cynipidae, I have 

 been deeply interested in many of the questions that were 

 treated rather fully by Hermann Adler in his epoch-making 

 work on "Alternating Generations: a biological study of Oak 

 Galls and Gall Flies," published some fifteen years ago. At the 

 time (iSSi) Liechtenstein published his excellent translation I 

 was in correspondence with him, and also had on several previous 

 occasions the pleasure of joining in some of his observations at 

 Montpellier and in discussing with him some of the questions 

 involved. 



One of the most interesting points in the economy of the 

 Cynipidae is the mechanism of oviposition. It is interesting not 

 only because of the almost universal but erroneous assumption 

 by older authors that Cynipid galls owed their growth to the 

 action of some poison inserted in the plant tissue by the female 

 in the act of oviposition,* but also because of the extremely 

 long, curved and specialized nature of the ovipositor itself and of 

 the difficulty in following all the steps in the act. 



A number of years ago, desiring to make some original 

 observations and, if possible, confirm Adler's on the subject of 

 oviposition, as also to endeavor to connect some alternate agamic 

 and sexual forms, I had a series of experiments instituted, plac 

 ing them in the care of Mr. Pergande. A number of young oak 

 trees of different species, in pots, were obtained for this purpose 

 and to assist observations in the field. Frequent absences from 

 the office, and other pre-occupations, prevented as much personal 

 attention as I had desired to give to the matter, and the experiments 

 were finally allowed to lapse. Some interesting observations, 

 however, have been obtained on the subject of oviposition ; and 

 as the results seem to conflict with those obtained by Adler, I 

 have concluded to put them on record, more particularly as an 

 English translation of Adler's celebrated work has recently 

 appeared from the Clarendon Press of Oxford, edited by 

 Charles R. Straton. 



Adler goes into details and seems to have made his observa 

 tions so carefully that one may scarcely doubt the accuracy of his 

 records. For instance, speaking of Neuroterus lenticularis, 

 which is the agamous spring form of Spathegaster baccarum, 

 he says: "It" (the female fly) " first examines the buds care 

 fully with its antennas until it finds one that suits it, when it 

 takes up a different position. It advances toward the apex of 

 the bud and pushes its ovipositor down under ,one of the 



*The ingenious dissertations of Walsh on the poison gland and the 

 secretion therefrom (Proc. Ent. Soc. Phil., II, pp. 473-4) very well illus- 

 strate how firmly this view was fixed in the minds of naturalists up to 

 that time. 



