88 



THE ENTOMOLOGIST S RECORD. 



Now, ajDplying this to the Hybernudae and Cheimatohia, we find 



that the facts do not bear out the theory. The first to appear, towards 

 the end of October, is H. defoliaria, with a truly apterous 2 (and how 

 wonderfully the various colours of the (? s of this species harmonise 

 with the autumnal tints of the various trees in a mixed woodland !) ; 

 this is followed in a few days by H. aurantiaria, with an almost 

 ajjterous J ; this again is shortly followed by the Cheimatohias, also 

 with nearly apterous J s ; then in January, H. rupicapraria appears, 

 with a very similar $ ; the next to appear, early in February, or, if 

 mild, at the end of January, is H. leucophaearia, with a strictly apterous 

 5 : followed m a day or two by H. marginaria, whose $ has the wings 

 most fully developed of all the Hyberniidae ; then later in the month 

 comes Anisopteryx aescularia, with a truly apterous 5 . Thus the series 

 begins and ends with the most ajDterous forms. Mr. Front's experience 

 is that H. marginaria and A. aescularia are contem23oraneous. In the 

 sense of both being out together no doubt they are, but still, here at all 

 events, the former precedes the latter to an appreciable extent ; I give 

 the dates of first captures of each for 1893 and 1894. Having had an 

 illuminated trap set every night each year in the same place, had either 

 been about earlier, I should certainly have taken it. H. marginaria — 

 1893, Jan. 28th; 1890, Feb. 3rd. A. aescularia— 189 S, Feb. 16th 

 (this seems to have been an abnormally early specimen, as no more 

 were taken till Feb. 28th, though the nights were favourable, and 

 H. marginaria taken regularly) ; 1894, Feb. 24th. 



Turning now to the Amphidasydae, Mr. Prout still thinks that the 

 wings of ? J., strataria are less developed than those oi 9 A. behdaria, 

 and is inclined to suspect that the former is " entirely unfitted for 

 flight." I do not think that the 2 s of either species fly much, but that 

 they both can and occasionally do fly is proved by my having taken 

 them both in my trap. To sum i;p, it seems clear that the increase and 

 decrease of the wing development of the 2 s does not coincide with the 

 increased and decreased severity of the season, and this seems to me a 

 great difticulty in the way of the theory that cold has any direct 

 influence ; indirect no doubt it has, as producing the causes which, as 

 pointed out by both Mr. Prout and Mr. Tutt, probably lead to disuse 

 and so atrophy of the wings. 



Looking at the Hyberniidae, especially at the remarkable similarity 

 in the variation of //. aurantiaria and H. marginaria, it is diflicult to 

 resist the conclusion that at all events the Hyberniidae and the Cheima- 

 tohias are descended from some common parent form, and it is not 

 improbable that this form was already partially apterous. The prin- 

 ciples of selection and survival of the fittest in each generation would 

 tend to preserve and intensify some special character, till the original 

 varieties became so far divergent as to be entitled to rank as new 

 species, gradually differing more and more from the original stem form 

 which, in accordance with Darwin's theory (Origin of Species) has 

 probably long since become extinct. This would account for a group of 

 moths, in many ways related to each other, all possessed of apterous or 

 semi-apterous 2 s ; for this attribute of the parent form, being useful 

 for the 2:)reservation of the species, would never be lost, though some 

 memljers of the group might and probably would become more 

 specialised in this direction than others. If this be so, it would only 

 remain to ^find some reason why the 2 of this parent form ceased to 



