170 THE ENTOMOLOGIST. 



even by climatic conditions. To begin with, I should incline to 

 explain all cases of retrogressive variations by want of food or 

 generally unhealthy conditions ; pigments, it must be remem- 

 bered, are physiologically waste products, and I could count upon 

 the support at least of such authors as Geddes and Thomson for 

 the view that when nutrition is low the profusion of katobolism 

 is much diminished, and little or no pigment produced. If, then, 

 it should appear that an atmospherically unfavourable season, or 

 the proximity of factories, tended to produce any (retrogressive) 

 varieties, such facts would be easily explicable, just as much as a 

 similar production of varieties by bad or insufficient food. It 

 will, I think, appear upon examination that several arguments 

 converge to support this view, and, first of all, I will point out 

 that most of the varieties chronicled seem to be retrogressive 

 ones, the commonest of all, viz., yellow varieties of red species, 

 being clearly such : of the progressive varieties I will speak anon. 

 Now, one fact that has appeared to me to possibly support 

 this position, is the variation of Colias edusa to helice. This 

 white variety is, I believe, confined to the female ; and if we 

 consider that pigments imply " waste energy," that they are nearly 

 always more abundant and richer in the male than in the female, 

 it does appear to me as not impossible that such varieties as helice 

 may betoken a deficiency of katobolic energy, that, in short, they 

 may be a starvation phenomenon ; that such phenomena should 

 occur exclusively in the female would be due to the fact that in 

 the female there is always less surplusage of katobolic products, 

 and that, therefore, the pigment is more likely to fail them than 

 the male.* 



(To be concluded.) 



ENTOMOLOGICAL NOTES, CAPTURES, &o. 



NoTODONTA TREPiDA AT ELECTRIC LiGHT. — I beg to report the capture 

 of a specimen of Notodonta trepida, which I took at electric light on June 

 6th. — 0. Farrant ; Taunton, Somerset. 



Note on Larv^ of Nudaria mundana. — When in Gloucestershire, 

 on the Cotswolds, last summer, I found on one occasion a number of small 

 larvae, pale brown in colour and somewhat hairy, congregated together on 

 an old wooden rustic gate. On looking closely, I found they were feeding 

 on a green lichen on the wood. Taking a few of them, I fed them on the 

 green lichen on pieces of the bark of larch firs ; they ultimately turned to 

 small pale pupae, in a slight web, and emerged as Nudaria mundana. I 

 have always found this moth common on the Cotswolds, but have not 

 seen it in this district, neither in parts of South Wales ; so apparently it 



* I am aware that this may sound very like definitely adopting the views for 

 which Geddes and Thomson were somewhat severely criticised ; but, as a matter of 

 fact, I am rather throwing out a suggestion than proposing a definite hypothesis. 



