CURRENT NOTES. 179 



travelled from the Mediterranean sliores to Kent, takes up a given 

 position on the roadside, and continues on flight in a space of some 6U 

 yards until it has laid its eggs, when deatli ensues, but so it apjiears to 

 be. Plusia (jamiita, in very poor condition, pallid, and of a very different 

 type to our bred British specimens of the autumn, has also abounded 

 since the commencement of June. 



In our March number (p. 72) we called attention to a note by Dr. 

 Knaggs, ridiculing the notion that sex might be in some degree 

 controlled by food. Considering the amount of time that is being 

 expended on the subjects of " Heredity " and " Germ cells," it seems 

 to us rather ridiculous that a man should go out of his way in argument 

 to bring forward an ex23eriment which had no very direct bearing on 

 the question at issue, and which was shown at the time by Professor 

 Kiley to be based on an entirely fortuitous coincidence, and not on 

 results capable of generalisation. Messrs. Geddes and Thompson 

 unfortunately quote this experiment, and hence have given widespread 

 distribution to an erroneous deduction. It is well known now, thanks 

 to the researches of Professor Poidton and others, what was not 

 generally known at the time of Mrs. Treat's experiments, that the sex 

 of an insect is determined at a comparatively early stage of the larva 

 and, probably, even as soon as fertilisation is effected. But to throw 

 cold water on experiment, and to suppose that there is no connection 

 between nutrition and sex, when experiments by noted biologists tend 

 to prove the contrary, only illustrates the fact that the science of 

 entomology is in some entomologists' minds a thing ajiart from the 

 general subject of biology. A note by Dr. Knaggs in the current 

 number of the E. M. M. is, therefore, interesting. He states in one 

 place — what is now well-known — that larvje have sex, and speaks of 

 " female larva3 when their ovaries are generally supposed to be furnished 

 with eggs," and yet takes a page to ask innocent experimenters to waste 

 their time on larvje of Orgyia antiqna, to prove that such sexed larvee 

 can have their sex changed by nutrition. No doubt this is interesting, 

 but the young experimenter will probably assert that this is only one 

 person's work. What we had to complain of before was the ridicule 

 thrown on the general principle, but things are now changed. The 

 doctor now writes : — " The effect of nutrition, or deficient nutrition to 

 shape the future sex of the hermaphrodite or sex-less embryo one can 

 comjirehend ; the rearing of males, and the failure to rear females by 

 semi-starvation, is by no means difficult to explain." This is all we ask 

 for. So much scientific men have proved or attempted to prove and so 

 much they present for acceptation, and if Dr. Knaggs had gone back to 

 this point in his previous arguments, we should not have found ourselves 

 compelled to disagree with him. Having granted so much, would it 

 not be better for Dr. Knaggs himself to experiment on the embryonic 

 cell or ovum when in a neutral state and give his results, rather than 

 to set our young recruits, who know no better, to rear " hundreds " of 

 Orgyia antiqna larvas when " their ovaries are generally supposed to be 

 furnished with eggs," in order to get male moths from female larvjB ? 

 The following information in a foot-note is quite news to xxs and we 

 thank the Doctor heartily for it : — " Malpighi (de Bomhyce, 29) dis- 

 covered eggs in the silkworm larva, and Reaumur {Mem. In., 359) 

 discovered eggs in the larva of the Gipsy moth." 



