COLIAS EDUSA, FAB. (CROCEUS, FOURC.). 139 
lucerne fields and clovers of all France are at disposition. At 
present we have no reliable evidence that the Hdusa on the wing 
in the Rivieran winter months is a wanderer. The evidence of 
its stability as a continuous-brooded species hereabouts is all 
the other way. Further, there is, I believe, no authority for the 
hibernation, sensw stricto, of the imago in this or any other 
locality.* The emergence of the autumn generation, September, 
October, November, may be finished at the end of the latter 
month, and oviposition is not likely to take place later; but the 
imagines may continue on the wing (both sexes) in December 
and January, and until worn out in the ordinary course of Nature. 
Commander J.J. Walker (‘Ent. Mo. Mag.,’ xxiv, p. 176) observes 
that at Gibraltar there is scarcely a sunny day in any month 
on which Colias edusa may not be met with in sheltered places, 
and Tutt,* rightly, I think, draws the conclusion that during the 
winter the larve of the Mediterranean first brood are feeding 
simultaneously, with only a very short pupal period. 
On the other hand, judging from the appearance and size of 
the immigrants arriving in England in May, when the second 
French Riviera generation is as yet not fully developed, it is, in 
my opinion, open to doubt whether after all our Hdusa are partly 
the offspring of these parents, as also presumed by Tutt (op. cit., 
ix, 280), but are typical Hdusa derived from and impregnated in 
remoter and warmer regions where the mean temperature of the 
winter is higher, for though by no means unusual, male Hdusa 
advena are rare in the United Kingdom. Tutt collected carefully 
all the evidence to date (1899) in the matter of Colias migration, 
and the reader may be referred in relation to this habit of the 
genus to his papers on ‘‘The Migration and Dispersal of Insects 
Lepidoptera,” published in the ‘ Entomologist’s Record ’ in 1900 
(vol. xii, pp. 70-72). He does not touch on the sex question, and 
the records of the great Hdusa year (1877) in the ‘ Entomologist,’ 
vol. x, pp. 187-190, 209-10, ete., are not very helpful, as 
observers in most instances are equally reticent. We have 
authority, however (‘Entomologist,’ loc. cit., p. 210), for captures 
in cdp. in such widely separated localities as Hants and Berwick- 
shire in June; but Carrington’s conclusion is that these were the 
results of successful intra-insular hibernation of the pupa, since 
apparently at this date it was not known to British entomologists 
that Hdusa passes the winter proper in the larval state, and 
though capable of enduring slight frost (which Hyale is not), is 
incapable of sustaining life through a normal Knglish winter. 
Be this as it may, I think the significant abundance of the 
species in the early part of the year in Cornwall at Land’s End, 
and the records referred to, point to migration of both sexes, 
aided or not by the progeny of the previous year’s migrants. 
In 1878 Edusa was reported on April 18th between Reading and 
* « How Colias edusa Winters,” ‘ Entomologist’s Record,’ vii, pp. 250-253. 
