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 larve 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 larve 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 whether any truth exists in the statements of old 
authors that larve differ in colour according to sex, Mr. 
Briggs experimented upon two forms of the larva of Trichiura 
Crategi; one form being ringed, somewhat like the larva of 
Bombyx Rubi; the other mottled. These forms were figured 
by Hiibner 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 larve 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 lineata.—Mr. Dunning read the fol- 
lowing 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 
swarms 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- 
