1894.] 165 



testing the accuracy of the assertion that females can be converted into males, and vice 

 versa, by the agency of food. I mention Orgyia antiqua partly because it is common, 

 and does not take long to feed up, but chiefly because it appears to present the best 

 chance of distinguishing the sexes in the larval state, particularly after the last 

 moult, when it is popularly believed that under ordinary circumstances the larger 

 larvae will produce females, the smaller males. 



In order to put to the proof the statement that serai-starvation will change 

 females into males, I would suggest, as a first experiment, that a batch of say a 

 hundred larvae should be reared ab ovo on a plentiful nutritious diet in a spacious 

 and well-ventilated cage, for the purpose of finding out the number of males which 

 are usually produced by unstinted feeding ; then another batch of a hundred should 

 be treated on the short commons principle, with a view to showing how many more 

 than the average number of males will result. Another way would be to feed up, 

 with fresh and frequent supplies of food, say a couple of hundred larvae until the 

 last moult, and then to select a score of the very largest for the starving process, and 

 a score of the very smallest for high living. 



Perhaps the following extract from Mrs. Treat's paper (Am. Nat., vii, 129) will 

 give the cue to any one who may care to go into the question : — " Soon after the 

 last moult, I took twenty larvae [of Papilio asterias"] and shut them away from food 

 for twenty-four hours, at the end of that time I replaced ten on a good supply of 

 food, watched them carefully, and kept them eating until they attained a large size ; 

 they became chrysalides within a few hours of each other, and emerged as butterflies 

 eight days after ; one of the chrysalides was accidentally crushed, the remaining 

 nine were females ; of the starved ones, eight males came out, the remaining two 

 chrysalides died." Messrs. Geddes and Thompson (Evolution of Sex, p. 46) thus 

 endorse Mrs. Treat's inferences : — " Still keeping to insects, we may note Mrs. 

 Treat's interesting experiments, that if caterpillars were shut up and starved before 

 entering the chrysalis state, the resultant butterflies were males ; while others of the 

 same brood, highly nourished, came out females."* 



The effect of nutrition, or deficient nutrition, to shape the future sex of the 

 hermaphrodite or sexless embryo one can comprehend ; the rearing of males, and 

 the failure to rear females, by semi-starvation, is by no means difficult to explain ; 

 but the assertion that female larvae, especially at a stage when their ovaries are 

 generally supposed to be furnished with egg8,t can be converted into males appears 

 to me to require further confirmation. — H. Guard Kkaggs, London, N.W. : 

 June, 1894. 



Birmingham: Entomological Society : Whitsuntide Excursion, 1894. — 

 A small party from this Society spent from May 12th to 15th in the neighbourhood 

 of Selsley on the Cotswolds. In consequence of poor weather, the collections made 

 were below expectations, and, consequently, there was some disappointment. The 

 Lepidopterists took numbers of larvae of Callimorpha dominula, Nemeophila plan- 

 taginis, Nudaria mundana, &c., and found Nemeobius lucina and other insects on 



• Dr. Landois (Zeit. fUr wissen. Z., B. 17, S. 375) was, I believe, the originator of this theory. 



t Malpighi (de Bombyce, 29' discovered eggs in the silkworm larva, and Reaumur (Mem., I, 

 359) discovered eggs in the larva of the gipsy-moth. These are old authorities, but I am not 

 aware that their accuracy hsis been disputed. — H. G. K. 



