IN THE BRITISH ISLAKDS. 11 



3. Family : Bombycoidce, Bdv. 



This family is chiefly composed of the old genus Acronycta, now 

 subdivided by Dr. T. A. Chapman into Viminia, Cuspidia and Bisulcia. 

 There is, in this family, a tendency to darkening of the ground-colour 

 in most of the species. The species have generally, in their paler 

 forms, a white or whitish-grey ground colour, the grey becoming more 

 and more intense until we get definitely suffused specimens as the var. 

 suffusa of psf,var. bradyporina of leporina, var. candelisequa of aceris and 

 var. myricce of euphorbice. We get, however, a few cases of almost ex- 

 treme melanism, notably var. nigra of ligustri, var. solids (?) of 

 menyanthidis and var. salicis of rumicis. Besides this general 

 variation, we find many species which have the darker colouring 

 collected into banded form, as in tridens var. virga, psi var. bivirgce, 

 leporina var. semivirga. The beautiful rosy tint, noticed in some 

 species of the CYMATOPHORID^E. is, in some species of this group, very 

 marked. Of this Guenee writes (' Noctuelles,' vol. v., p. 47) : 

 "Almost all the species of this genus have now and again isolated 

 individuals distinctly suffused with rose colour." Mr. N. F. Dobree 

 writes me with reference to this rose coloured suffusion : " A lot of 

 larvas of A. megacephala were sent me in 1875 by a person living at 

 Forest Gate, and the resulting insects retain, even at the present day, 

 a distinctly rosy tinge." Hiibner figures two specimens of megacephala : 

 one, fig. 10, is the ordinary continental type, the other, fig. 11, is 

 decidedly suffused with red. Some specimens of Moma orion have all 

 the white markings suffused with rose colour. Dr. Chapman of Here- 

 ford, who has paid particular attention to this group, sent me some 

 beautiful rosy specimens of tridens and psi. He also sent me specimens 

 of a remarkable local race of psi which he calls bidens. This form has 

 structural characters by which it can be definitely distinguished from 

 psi, much more readily than can the latter species from tridens. I 

 would also call attention to the development of the fringe markings in 

 this group. The double fringe line at the anal angle occurs, I think, 

 in all the Acronycta also in cceruleocephala, but there are few other 

 NOCTU^E that have the fringe markings so well developed as the mem- 

 bers of this genus." 



Moma, Hb., orion, Esp. 



This beautiful species offers a little variation in the depth of the 

 ground colour and a little in the development of the markings, while 

 the peculiar orbicular and reniform appear to vary endlessly; occasion- 

 ally also there is some variation in the amount of fuscous shading 

 outside the exterior transverse line. In some specimens, the central 

 and exterior transverse black lines are more or less double, giving such 

 examples a darker appearance, which led our early British authors to 

 suppose that we had two species. Newman figures both. Esper's type 

 has two longitudinal white lines, both starting from the base, one 

 passing under the median nervure to the anal angle, the other through 

 the stigmata. Many of our specimens are without the upper one. 

 Esper's type (represented by fig. 4, Plate 118), may be described 

 as having the anterior wings of a beautiful green ground colour with 



