76 THE ENTOMOLOGIST. 



specimen, and this also has the white coloration. Var. pallida, 

 Tutt. is described as white, with the markings almost obsolete, 

 and fig. 1 is possibly near this. Figs. 3-5 are grey forms, and 

 are more or less typical examples of the species, and figs. 6-10 

 show various modifications of the melanic race occurring in the 

 Delamere Forest, from which locality the specimens 3 and 5 were 

 also obtained. Of the melanic forms, figs. 8 and 10 represent 

 rohsoni, Collins, and thompsoni, Arkle, respectively. Except that 

 fig. 10 has a white crenulate line on the outer margin of the fore 

 wings, and that the fringes are white instead of brownish grey, 

 it is not otherwise very clearly separable from fig. 8, which has 

 been recognized by Mr. Collins as agreeing with his type of 

 rohsoni. ISIow, it will readily be seen that figs. 6 and 9 are more 

 unlike figs 8 and 10 than the latter are to each other. It follows 

 then that if it be considered necessary to have names for two 

 modifications of the melanic race, names must also be given to 

 all melanic specimens that are not identical with figs. 8 or 10. 

 Further, the process would not end here, but would have to be 

 extended to the various gradations in the grey form, and to those 

 in the white form also. An alternative course would be to use 

 varietal names only for the main departures from the typical 

 grey coloration, and these are already provided — in pallida for 

 the white ground forms, and rohsoni for the black forms. 



The grey form is perhaps more generally distributed in 

 Britain than either of the others, but in some counties — as, for 

 example, in Berkshire — the grey and the white forms both occur, 

 but not in the same wood. The white form appears to be the 

 dominant one in the West of England and in Ireland, and 

 examples of it have been found in Scotland. The melanic form 

 is confined to Delamere Forest and South Yorkshire. Mr. A. 

 Harrison informs me that this form is certainly increasing in 

 numbers in the Cheshire locality. From larvae collected there 

 in 1905 he reared 11 per cent, of the melanic form, and of these 

 one specimen only had pure white fringes (fig. 10). In 1904 the 

 melanic specimens had been only 5 per cent., and in several 

 previous years the number had been lower than 5 per cent. 



Mr. Harrison adds : — "The larvae of A. nehidosa are mostly 

 found on young birch trees, a few only occurring on sallow, haw- 

 thorn, and bramble. They outnumbered all the other Noctuid 

 larvae put together in the part of Delamere Forest that I collected 

 in. They are far more numerous in the Cheshire locality than 

 in Epping Forest or the New Forest — at least, that has been my 

 experience." 



Richard South. 



