i893.] THE BRITISH NATURALIST. 71 



increase of factories, chemical works, blast furnaces, and such like 

 smoke and fume producing places, which have been established during 

 the last half century, and, as they have increased in number, so have 

 two facts in connection with Lepidoptera become apparent. First, 

 the more delicate species have become' extinct, and Second, the more 

 susceptible have become melanic. There is considerable difference to 

 be observed in the susceptibility of different species. The first noticed 

 in this country was Amphydasis betularia, and singularly enough, it has 

 apparently been the first species to become melanic in the manufactur- 

 ing districts of Germany. Red, green, and black, are the most 

 heat-absorbing colours, and Lord Walsingham has proved that in 

 black this applies to insects, and he has also shown that it is probably 

 so with red. With reference to green it is somewhat singular that in 

 my district Polia chi has become green under the clouds of smoke, 

 whilst in the Yorkshire districts it tends towards black. Eupithecia 

 rectangulata which is normally green, has under these smoky clouds of 

 both London and Newcastle become quite black. There are many other 

 apparent anomalies, thus, Irish male Mendica are not black, but nearly 

 white, and the genus Fidonia is found to have a whiter ground colour 

 in the North and a yellower in the South, and with the closely allied 

 Stroma clathmta the same rule obtains. But no doubt all these 

 apparent difficulties will be explained in due time ; the chemistry of 

 insect colours has scarcely been studied at all. At present we 

 may confidently assert that whatever impedes the direct rays of the 

 sun, has a tendency to create melanic forms in Lepidoptera. 



THE PTEROPHORINA OF BRITAIN. 



BY. J. W. TUTT, F.E.S. 

 (Continued from p. 58). 



Leioptilus tephmdactyla, Hb. — This species is also local in Britain, 

 though it appears to be much more widely distributed than lienigiamis, 

 but less so than osteodactyla. 



Synonymy — Tephmdactyla, Hb., 17; Zell., 'Linn. Ent. Zeit.,' VI., 

 382; Ev. < Fauna Volgo-Ural.,' 608; H.-S., 28, V., p. 380 ; Frey, 

 415 ; Tgstr. ' Anm.,' 200 ; Sta. ' Man.,' II., p. 443. This is one of 

 those few species which appear to have no synonyms, but which has 

 always been recognised by the name by which it is now known. 



Imago — The fore-wings are divided into two lobes ; the apex 

 pointed ; the colour greyish-ochreous, thickly mottled with blackish- 

 grey scales, giving the wings a very suffused appearance ; at the end 

 of the cleft are two small blackish dots, that nearest the costa being- 



