J. W. H. Harrison and L. Doncastbr 233 



consequence of the fact that, whilst there is but little difference in the 

 wings of various specimens of hirturia females, in the apterous forms 

 there is an extraordinary amount of variability. 



In lapponaria, for instance, the wings vary from mere vestiges to 

 long lanceolate appendages and similarly with pomonaria; zonaria on 

 the contrary, although not quite constant, for it varies slightly in the 

 same direction, is almost so. The hybrids have thus to combine the 

 immutability of the female wings of hirturia with the varying forms 

 developed in the other species. The result is that, whilst in most cases 

 we have wings produced resembling very roughly ordinary male wings, 

 although only two-thirds of the expanse, in many, we have long, narrow 

 pointed wings, and in others, wings most curiously shortened, giving one 

 the notion tliat a piece has been cut fi-om them. As one might expect, 

 the variation is least in the zonaria ^ — hirtaria % cross and greatest in 

 the two hirtaria — pomonaria crosses. 



Nor is the variation confined to size and shape for, strange to say, 

 the wing scales vary simultaneously ; the smaller the wings the greater 

 the tendency for the .scales and fringes to become bristle or hair-like as 

 in normal apterous females. Further, although the rudimentary wings 

 of the apterous forms are not melanic, nevertheless the smaller the 

 wings in the hybrids the gi'eater the melanic tendency, which, however, 

 it must be remarked, is present in all of the female hybrids. 



In crosses between the apterous forms, in the majority of cases, the 

 wings are small and constant, and seem greatly influenced by the wing 

 form of zonaria. 



The tendency of hybrid brooksi to produce forms with all the 

 possible wing sliapes combined in one specimen has already been 

 noticed. 



The wing forms of the other two secondary hybrids demand special 

 attention. The females yielded by the crossing hunii ^ and hirtaria % 

 possess forewings about five-sixths of the normal wing expanse of 

 hirtaria J* but with the inner margin shortened, and the costa and 

 termen strongly rounded. The hindwings, except that they are pro- 

 portionately stouter and broader, are not unlike those of hunii $ . The 

 scaling of both sets is that of hirtaria % ; the markings, too, except that 

 the fringes are quite black, follow hirtaria. 



The hybrid between pz'kii ^ and hirtaria $ very curiously produces 

 females, which, except for the slightly rounded costa and termen, have 

 both sets of wings almost, but not quite, as fully developed as those of 

 hirtaria $ . If the predominant influence of the male, as mentioned 



