2/2 THE STUDY OF INSECTS. 



The moths are of medium size, sometimes small, but only 

 rarely very large. Usually the body is slender, and the 

 wings broad and delicate in appearance. This appearance is 

 due to the fineness of the scales with which the wings are 

 clothed. These moths occur on the borders of woods and in 

 forests, rarely in meadows and pastures. Their flight is 

 neither strong nor long sustained. When at rest the wings 

 are spread horizontally and scarcely overlap each other. 



The distinguishing features in the venation of the wings 

 of the Geometrina are that vein V s of the fore wings is not 

 more closely joined to cubitus than to radius, 

 cubitus being apparently three-branched, and 

 that the basal part of vein II of the hind 

 wings makes a prominent bend into the hu- 

 meral angle of the wing (Figs. 322, 323).* 

 Except in the more specialized forms where 

 it has disappeared there is a rudiment of vein I of the 

 hind wings. This usually extends from near the base of the 

 frenulum to the angle in vein II (Figs. 322, 324). In Eudule 

 (Fig. 323) and allied forms the rudiment of vein I lies some 

 distance from the margin of the wing. 



There occur in our fauna representatives of five families; 

 these can be separated by the following table : 



A. Vein V 2 of the hind wings wanting, being represented merely by a 

 fold in the wing (Fig. 327). p. 277. ENNOMID^:. 



AA. Vein V 2 of the hind wings present. 



B. Vein V 2 of the hind wings arising much nearer to vein Vi than 

 to vein V 3 (Fig. 343). Wings usually green, p. 287. 



GEOMETRID/E. 



BB. Vein V 2 of the hind wings arising nearly midway between 

 veins Vi and V 3 or nearer to vein V 3 than to vein Vi. Wings 

 rarely green. 



* In the more specialized forms the humeral angle is greatly expanded 

 (Fig. 343), and in some the frenulum is completely supplanted by it (Fig. 335). 

 The loss of the frenulum in this family, however, occurs only in highly spe- 

 cialized forms ; while in that series of families that we have called the Fren- 

 ulum-losers it has occurred in all except a very few extremely generalized 

 forms. 



