78 HYMENOPTERA. 



albilabris and hrevis ; Oxyhelus uniglumis ; Odynerus pa- 

 rietum ; Vespa vulgaris^ gernianica and ryfa„ 



The wasps were very abundant, jjarticularly so in the 

 butchers' shops. I was pleased to find that the butchers at 

 Cromer have observed that wasps, if unmolested, are per- 

 fectly harmless, and extremely useful in carrying off the 

 large blow-flies; the butchers at Cromer are always, they 

 say, glad to see plenty of wasps. Some people begrudge 

 wasps a little fruit, and appear to have no idea of the many 

 ways in which these insects are beneficial. 



Mr. Algernon Chapman has this season captured the rare 

 Odynerus crasdcornis, at Abergavenny; and also, the equally 

 rare PompUus hifasciatus. 



I have previously remarked upon species of saw-flies that 

 are of common occurrence, of which only the females have 

 been discovered ; and I have shown that breeding numbers 

 of one of these species has failed to produce the male sex. 

 This is, I admit, no conclusive proof of the non-existence of 

 that sex, but we are led to ask ourselves, whether copulation 

 at remote intervals is not, in these species, the law which 

 regulates their continuance. 



A subject equally interesting, and one that embraces per- 

 haps even more startling phenomena, is the law that de- 

 termines the development of the sexes in insects. A most 

 interesting paper on this subject appeared in the Annals and 

 Magazine of Natural History for 1867. This paper is a 

 translation from the " Comptes Rendus." The author of the 

 paper, Landois, endeavours to prove that the sex, in insects, 

 is not determined in the egg state, and that it entirely depends 

 upon the abundance or deficiency of food supplied to the 

 larva; this naturally calls to mind the opinion of Huber, who 

 refers the cause of difference of sex entirely to the quality of 

 the food with which the larva is suppHed; the development 



