50 [October 



Hartig observes that if these insects had been obtained by catching, 

 the absence of the males might be explained by their escaping, in some 

 way or other, our prosecution ; but, says he, this supposition is not admiss- 

 ible for insects obtained by rearing; he was compelled to conclude, there- 

 fore, that these insects were agamous, or, in other words, that the males 

 did not exist at all. 



In a communication made to the Academy of Sciences in Philadel- 

 phia and which is published in its Proceedings (July, 1861), I have re- 

 ported on an observation, which, if confirmed, would solve the question 

 of the sexes of Ct/nipidse. From a singular, spindle-shaped gall on the 

 red oak, I reared a male Cynijn which is very similar to the gall-fly of 

 the common oak-apple of the red oak, C^mps confluent Harris, known in 

 the female sex only and looks exactly as one might suppose the % Cj/nip^ 

 conjiuens, if known, ought to look. If it is proved that the Gynips of the 

 spindle-shaped gall is the male of the Ot/nlps of the oak-apple, and if it is 

 shown, by further observation, that in the genera, supposed agamous by 

 Hartig, the males produced from galls are different from those of the females, 

 then it will be plain how 28,000 galls of the same kind could give lO.UOU 

 females and not a single male. 



A strong proof in confirmation of my assertion is, that in those genera, 

 the males of which are known, both sexes are obtained from galls in al- 

 most equal numbers, even the males, not unfrequently, predominate in num- 

 ber (see Hartig, 1. c. IV, 399). Now the gall-flies reared by me fi-om the oak 

 apple were all females; Dr. Fitch also, had only females; and Mr. B. D. 

 Walsh, in Hock Island, 111., reared (from oak-apples of a different kind) 

 from 85 to 40 females, without a single male. This leads to the conclu- 

 sion that the Cynipes of the oak-apples belong to the genera hitherto sup- 

 posed to be agamous. If the characters of Ilartig's subdivisions were giv- 

 en more in detail, the simplest way of testing the question would, of course, 

 be found in those characters; they would decide at once whether Ci/nips 

 conjiuens really belongs to Hartig's agamous genera and whether the dis- 

 covery of a male is a novelty in science or not. 



I will state some other questions, deserving the especial attention of 

 future observers. 



Most of the gall-flies always attack the same kind of oak ; thus the gall 

 of (J. seminator Harris, is always found on the white oak; ('. tuhicola 0. S. 

 on the post oak etc. Still some galls of the same form occur on different 

 oaks; a gall closely resembling that of V. qiirrcus (jf<jl>u/iis Fitch, of the 

 white oak occurs also on the post oak and the swamp chestnut oak; a gall 

 very similar to the common oak-apple of the red oak <iceurs on the l)lack- 

 jack oak etc. Are such galls identical, that is. are they produced by a 



