24 THE ENTOMOLOGIST. 



Besides the species just adverted to, there are now in Yorkshire at 

 least thirty others " in which melanism has become so strongly 

 developed that in various districts — chiefly in the south-west — black 

 or nearly black specimens of species, which in other districts are pale, 

 are now regularly obtained." As regards eight or nine of these me- 

 lanism is not of recent development, but in the case of the remainder 

 " dark specimens have largely increased in numbers during the collect- 

 ing experience of our present-day lepidopterists." 



In the matter of hereditary transmission, Mr. Porritt gives some 

 interesting illustrations. In 1904 he reared nine moths from a few 

 eggs deposited by a black female Odontopera bidentata. Six of these 

 were black like the female parent, and the other three of the ordiuary 

 form. " From the black moths in the following year. 1905," he 

 states, " I reared a very large brood, about 75 per cent, of which were 

 black ; and from these again this year [1906] I bred a considerable 

 number, of which the percentage of black was still greater." 



Larentia multistrigaria is stated to be fast becoming entirely melanic 

 in certain districts in Yorkshire, and it has been found by experiment 

 that three generations reared in captivity have almost entirely elimi- 

 nated the typical form of this species ; among seventy specimens 

 reared in the spring of 1906 there were only five or six pale ones. 



Again, a male and a female of the largely black variety of Abraxas 

 grossitiariata, known as ab. varleyata, were reared from collected larvae. 

 These paired, ova were obtained, and from them a large brood of the 

 moth was reared, all of the parent form, i.e. varleyata, and in no 

 instance was any tendency shown of a return to the ordinary or any other 

 form of the species. In the few localities known to yield ab. varleyata, 

 specimens of the variety " reared by collectors only average about 

 three for every thousand larva}" ; thus the chances of the sexes of the 

 variety pairing in a wild state are exceedingly slender. 



Mr. Porritt also points out that, although melanism affects certain 

 species in South-west Yorkshire, other species occurring in the same 

 area, and of which there are melanic forms in other parts of Britain, 

 are in the district he deals with either normal or exhibit a tendency to 

 leucochroism. In this connection he instances Cidaria sujfumata, 

 among other species. Of G. suffumata, the dark form piceata, which is 

 common in Scotland, and also occurs in North Yorkshire, is scarcely 

 known at all to the collectors in the melanic area of South-west York- 

 shire. The species as it occurs there would seem to be becoming paler 

 and generally modified in the direction of the variety, with pale clear 

 ground and dark baud, known as the "Dover form." 



There is very much more in this exceedingly interesting paper to 

 which we should like to refer, but our readers no doubt will make a 

 point of perusing it themselves. They will find it much to their 

 advantage to do so. 



