﻿NOTES, CAPTURES, ETC. 133 



sugar on August 19th a freshly emerged specimen of Dianthoecia cucubali, 

 and on August 30th I captured a solitary specimen of Emmelesia albulata, 

 disturbed from amongst a great quantity of its food-plant, the yellow rattle. 

 Would these be deferred emergences or a second brood ? — T. B. Jefferys ; 

 Bath, March 5, 1890. 



[D. cucubali has been taken and bred in August, and E. albulata 

 captured in September. Vide Entom. xiv. p. 214; vi. p. 429.— Ed. J 



Abundance of Vanessa cardui in New Zealand. — Since my last 

 note (Entom. p. 20), I have observed Vanessa cardui in increasing 

 numbers. During October I saw over six specimens in different localities 

 near Wellington ; while on Nov. 3rd sixteen or seventeen specimens were 

 to be seen in openings in the forest near Karori. I also observed several of 

 these butterflies in the middle of the month, during a brief stay at Palmerston 

 North, a locality some eighty miles to the north of Wellington. In England 

 I believe it is the fashion to attribute the sudden appearance of certain species 

 of insects to migration from the Continent of Europe, but in New Zealand 

 such explanations are obviously quite untenable. I am inclined to believe 

 that the abundance, or the reverse, of a given species, is largely determined 

 by certain conditions of existence, with which we are at present most 

 imperfectly acquainted, and that in the case of a periodical insect like 

 V. cardui, these conditions ooly recur occasionally, the species being so ex- 

 tremely rare during the intervening seasons, that it altogether escapes our 

 observation. It is, of course, almost certain that insect migrations 

 sometimes occur, but we should always remember, that in animals endowed 

 with such enormous reproductive powers as insects, any circumstance 

 tending to lessen the rate of mortality in a given species, would at once 

 cause its numbers to increase with almost incredible rapidity. — Gr. V. 

 Hudson; Wellington, New Zealand, November 20, 1889. 



Temperature and Mklanism. — At a meeting of the Entomological 

 Society, on December 4th, Lord Walsingham staled that forcing pupae 

 produced in the imago a result the opposite of melanism. According to the 

 theory I have advocated (Cauad. Ent. 1888, p. 86), such colour-changes are 

 more strictly connected with the rate of development than with heat or cold 

 as such. If so, forcing throughout the whole or a large part of a 

 insect's life as a pupa ought, as stated by Lord Walsingham, to produce the 

 reverse of melanism; but if an insect is subjected to great cold throughout 

 the winter, and suddenly to great heat in spring, it ought (according to my 

 theory), as a rule, to show some tendency towards melanism. Now many 

 of your readers breed Lepidoptera ; will not some one try some experi- 

 ments to prove the point ? An experiment which might be tried by any 

 breeder of Lepidoptera this spring is as follows: — Take pupae which have 

 hybernated, and about a fortnight before the normal time of emergence 

 transfer them to a hot-house, or to some heated place. This might bring 

 the imagines out a few days earlier; but as the pupae wintered in the mild 

 English climate, I should doubt whether it would produce any perceptible 

 effect on the colouring of the insects. But should it produce any effect, a 

 melanic or dusky tendency would be favourable to my theory, while the 

 opposite tendency would seem to contradict it. These " temperature- 

 forms " are rather fully discussed in Entom. xxii. 27 — 29, to which I would 

 refer the reader. Temperature " melauisnis " are generally small, greyish, 

 suffused or dusky, and yellow and other bright colours are paler or partly 



