BY A. .TEFFEtllS tURNEH. 



305 



The curious structure kiiuwuas the fovea is useful as a generic 

 character and as indicating generic relationship. But, like all 

 secondary male characters, it must be used with caution. It is 

 certainly characteristic of the Boarmia group, though lost in 

 some genera {Ilybernia, Melanodes), and even in some species of 

 genera in which it is usually well marked (Ectropis, HeteroptUa}. 

 But it is also present occasionally in the Cashia-gvowp {Hypery- 

 thra, Casbia rectai'ia), and in several species of Amelora, as well as 

 in the closely related genera Angelia, AuthcKmon, and Faramelora. 

 It seems to have been developed independently in these two latter 

 instances, just as a similar but differently situated structure has 

 developed in the hind wing of Deilinia and the fore wing of 

 Neritodes. 



Owing to tlie variability of the neuration, particularly in the 

 Boanuia-gvoup, it is necessary to examine, wherever possible, a 

 series of each species. Only by so doing will the neuration be 

 properly understood, and some authors have fallen into unneces- 

 sary errors by neglect of it. Under the genus Boarmia will be 

 found some illustrations of this variability. It is important 

 also to recognise that neuration may be apparently identical 

 but morphologically distinguishable. 'J'o take a single example, 

 in Text-tig. 1, vein 10 is absent. This neuration is common in 



i^ig.l. 



Fig. 3. 



the gQwwa Boarmia, and as 10 and 11 are often long stalked in 

 the same species, it is evident that 10 has become coincident 

 with 11. But the same neuration occurs in Chrostobapla, and 

 with anastomotic variations in Lomoyrapha, in which genera, 

 there is reason to believe, 10 is coincident with 9. Text-fig.2 

 occurs in Boarmia and many other genera, and really, as ap- 

 parently, 10 and 11 arise long-stalked from cell. But in Mefro- 

 caiuna, the same neuration has not that sisniticance. For in 



