300 THE entomologist's record. 



spots. Here it is impossible for cold, acting on the pupae, to 

 have any effect in the direction of darkening the colour, as 

 those exposed to the winter cold are the paler forms, and I 

 can only suppose that the retardation in the early larval stage, 

 aided by " natural selection," is the true active cause of the 

 darkening, as the pale specimens, with their undersides 

 brightly yellow are more protected in early spring, when the 

 more common CrucifercB are in flower (white or yellow) and 

 the leaves are bright. In the summer the insects assimilate 

 by means of their darker colour (especially greyer undersides) 

 more closely to the darker leaves. The allied Pieris napi has 

 imagines of the spring brood with the ground colour dusky, 

 markings dusky-greyish ; the summer imagines have the 

 ground colour white, markings black. Comparing the two 

 species, my experience points to the second brood of P. napi 

 being in the larval stage longer than P. rapes, and I have 

 frequently known larvae to live from early August until October 

 before pupating. Although equally common perhaps, the 

 habits of these two species are very different, and whilst P. rapes 

 is more especially addicted in its early stages to open cultivated 

 grounds, P. napi prefers marshy land, ditch sides, shady rides 

 in woods, etc., so that environment and " natural selection " 

 undoubtedly have considerable effect. I still consider, how- 

 ever, that the study of the undersides is the more correct 

 method of dealing with all our butterflies, from the point of 

 view of " natural selection," but in these species the upper 

 sides are comparatively a reflex of the undersides, napi being 

 the darker in the early brood, and very similar to rapes in the 

 summer brood. The spring specimens of Lyccsna appear to 

 vary somewhat in a proportionate degree to the length of time 

 passed in the larval stage, and the peculiar habits of the 

 respective broods. 



{To be continued.) 



Scientific notes. 



The Genus Donacia^ Fab. {continued from p. 280). 

 D. iimbata, Panz. — Known as D. ienina', F., in Sharp's Catalogue of 

 Britisii Coleoptera (1871), and in Fowler and Matthews' Catalogue of 

 British Coleoptera (1883). This is another of the purple-striped species, 

 but the stripe is at the sides of the insect in this case, and there is also 

 a purple blotch near the base on each elytron. Rather common in 

 Kent, Surrey, and other southern counties. I have taken it at Sunbury, 



