THE ZOOLOGIST—SEPTEMBER, 1876. 5091 
in the female, widened towards the apex. ‘This season I have repeated my 
experiment, and have obtained a single male out of several hundreds of 
flies. 
“Mr. Cameron further observes, ‘In all probability they, like Cynips 
(lignicola) Kollari and other Cynipide, propagate without the aid of the 
male sex.’ This observation was undoubtedly made in ignorance of the 
discovery made by Mr. Walsh in 1868. In the « American Naturalist’ for 
that year, the author records the fact of having himself bred both sexes of 
Cynips spongifica from the galls of the black oak of North America. These 
galls resemble those of Cynips Kollari, being globular, rather larger than 
the European galls, but of the same hard woody consistency externally, 
and of the same spongy substance inside. Mr. Walsh adds, ‘ By the fore- 
part or middle of June both male and female gall-flies eat their way out 
of a certain number, say about one-fourth part; the remainder are not 
developed until about two months later. In a private communication 
from Mr. Walsh, I learnt that he had, like myself, bred hundreds of the 
gall-flies from gulls collected late in the autumn, all these proving to be 
females, and that it was not until he made collections of galls in summer, 
when a partial development of flies takes place, that he obtained the male, 
this sex being as one to many hundreds of females. At length he bred 
three males, one of which he kindly forwarded to me, and which 1 exhibited 
at a meeting of this Society. Following up Mr. Walsh's method of collecting 
the galls of Cynips Kollari early in the season,—that is, just at the time 
when they are becoming hardened, and before any flies have escaped from 
the fresh galls,—I have tried, but hitherto without success, to obtain males 
of Cynips; but I advise all who are interested in the matter to pursue the 
same plan, always remembering that these mysteries of nature are only 
unfolded at intervals, and then ouly to favoured votaries. 
“With respect to the obtaining of males of Nematus gallicola, I believe 
that any one may collect, even early in the season, thousands of the galls of 
that insect without obtaining a male; but in all probability, by persevering 
season after season, his efforts will, as in my own case, be crowned with 
success ; but I feel assured that unless the galls are gathered before any 
of the flies have escaped, he will have little or probably no chance of 
success. The same care must also be taken in collecting the galls of 
Cynips Kollari; collecting them early, just at the time when they harden 
and become woody, for it is out of the flies first developed that the male 
may be expected to be found. My having bred thousands upon thousands 
of flies without obtaining a male should prove a stimulus to others, for that 
a male exists I think Mr. Walsh has determined beyond question. The 
impregnation of a single female may possibly be sufficient to render her 
progeny, and their descendants, for several generations, equally fertile; and 
the same may possibly be the history of Nematus gallicola. The male bred 
