46 Journal New York Entomological Society, n'oi. xxv. 



The determination of the sexes is in general easy in the Geometri- 

 dse. Aside from the fact that the claspers of the male, and oviposi- 

 tor of the female can usually be seen, the multiple frenulum of the 

 female (which in the Geometridae is a bundle of bristles of unequal 

 strength) is characteristic, except in Operophtera, where it is multiple 

 in the male and the female is wingless. Operophtera has heavily 

 fasciculate antenucT unlike any female known to me. The simple 

 frenulum always marks the male in this family. In the Geometrinae 

 . and Palyadinae it will be necessary to combine the sexes in a single 

 table. 



The Dyspteridince have been combined with the Hydriomeninse, 

 for reasons already given by Pearsall ; the Mopotaxiinse are based on 

 a single sexual character which occurs in several otherwise unrelated 

 genera, and so the group has been dropped. Hulst's Monocteniinse 

 are entirely recast, as indicated by Prout in the Genera Insectorum. 

 Of his genera Melanonima is a Noctuid, and the other three are 

 Sterrhids of three different tribes. 



Notes have been added to the key giving changes in generic con- 

 tent and placing the more important exotic genera. I had hoped to 

 review the South American genera with some care, but Warren's 

 descriptions are so brief that I could make nothing of them, except 

 where I had a chance to see specimens in the U. S. National Museum. 

 Several of his names will have to be used' in our fauna, especially in 

 the Boarmid series, and for sections of Hydricmena. Meyrick does 

 not give the condition of the middle discocellular in the hind wing 

 in his papers, so that I was unable to place the genera not represented 

 in the American Museum of Natural History, but I have indicated 

 one or two places where I think his name may have to be used. A 

 surprisingly large proportion of the North American genera are rep- 

 resented in Australasia, in fact the family is more nearly cosmopolitan 

 than any other group I know. 



Key to Subfamilies of Geometrid^ : 



I. Wingless (females) 2 



I. Wings from about 1/16 inch long to pupal size (females) 3 



1. Wings slightly reduced or normal 5 



2. Hind tibia longer than tarsus, with well developed spurs ; moth brown, 



smoothly scaled Rachela in Hydriomeninae. 



