THE ENTOMOLOGIST. 297 



idea that the sex is determined by the supply of food (or its 

 quality) furnished to the larva, Mr. Briggs detailed some 

 experiments he had made. A number of larvae of Liparis 

 dispar were separated into two divisions, about sixty in each. 

 One lot were fed upon hawthorn, the other upon elm. In the 

 elm-fed larvae the imagos produced were about equal as 

 to sex, but there were only two perfect females ; the males of 

 the ordinary size. In those fed upon whitethorn, the sexes 

 were again about equal in number, but the males were much 

 smaller and paler, whereas the females were much finer, and 

 scarcely any of them imperfect. Again, with a view of deter- 

 mining w^iether any truth exists in the statements of old 

 authors that larvae differ in colour according to sex, Mr. 

 Briggs experimented upon two forms of the larva of Trichiura 

 Crataegi ; one form being ringed, somewhat like the larva of 

 Bombyx Rubi ; the other mottled. These forms were figured 

 by Hlibner as of different sexes ; but the first-named seemed 

 to be dying out, and was described by none of the more 

 recent writers. From a batch of eggs Mr. Briggs obtained 

 about thirty larvae of each form : firstly, a male imago, 

 produced from a larva of the ringed form, was paired with a 

 female of the mottled form ; secondly, these conditions were 

 reversed ; thirdly and fourthly, each form was paired with its 

 like. From these four experiments in no one instance was 

 the ringed form of larva obtained ; and it did not reappear 

 after breeding in to the third generation. 



Swarms of Chlorops Ihieata. — Mr. Dunning read the fol- 

 low'ing letter received from the Rev. L. Jenyns, of Belmont, 

 Bath : — " I see in the Proceedings of the Entomological 

 Society (Part v. 1870, p. xxxiv.) notice of a communication, 

 made at the Meeting of the 7th November, respecting large 

 sw^arms of flies, referred to Chlorops lineata, which had 

 appeared in September in a room in the Provost's Lodge at 

 King's College, Cambridge. It may be worth drawing the 

 attention of the Society to the circumstance of the same 

 phenomenon having occurred, probably in the same room, in 

 1831, thirty-nine years ago, where it was witnessed by myself, 

 the late Provost, Dr. Thackeray, having invited me to come 

 in and see it. Of that phenomenon I published a full account 

 at the time in Loudon's ' Magazine of Natural History' (vol. 

 V. p. 302), and it was afterwards reprinted in my * Observa- 



