THE ENTOMOLOGIST. 237 
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 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 forepart 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 galls 
collected late in the autumn, all these proving to be females; 
and that it was not until he made collections of galls in the 
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 I 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,—l 
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 
only to favoured votaries. With respect to the obtaining of 
males of Nematus gallicola, | believe that anyone 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 
