GEOMETRINA. 337 



Group 4. GEOMETRINA. 



This is also an extensive group of species. It is not very 

 closely allied to the last, but seems to run in other lines, with 

 perhaps, in some degree, a closer alliance to the Bombycina. 

 The arrangement usually followed in this country — that of 

 M. Guenee, as adopted by Mr. Stainton in his " Manual " — 

 seems to be open to a criticism similar to that to which his 

 arrangement of the Noctuina is exposed, of a separation into 

 families of which the structural characters are insufficient, or 

 of merely generic value. In this respect that followed by the 

 later German authors appears more satisfactory, though here 

 they mass together in single genera large numbers of species 

 which seem to be more reasonably placed in smaller ones. 

 We miss in the present group the extensive series of struc- 

 tural characters so useful in the subdivision of the Noctuina, 

 and are compelled to place more reliance on those which 

 remain. For instance, the eyes in the present group, although 

 usually large and prominent, are, I think, always devoid of 

 the covering of minute upright bristles found in so many of 

 the species of the previous ; and there is little, if any, indica- 

 tion, in the vast majority of the species, of the bordering 

 rows of bristles which I have denominated eye-lashes. Where 

 the eyes are less prominent — in stouter species — they are often 

 obscured by dense hair-scales which project from the head. 

 The collar is far less conspicuous — indeed, between it and 

 the head a small transverse ridge is commonly interposed — 

 or has become noticeable through the extension forward of 

 the head. The top crest, so conspicuous in many Noctuina, 

 seems to be invariably absent ; and the back crest, where 

 visible, is usually a mere short blunt undivided tuft of scales 

 extending across the back of the thorax. The abdomen, 

 though often possessing the lateral tufts, and always the 

 anal, is commonly quite devoid of any indication of dorsal 

 crests ; and even where these are present they are usually 



VOL. VI. y 



