684 



AN INTRODUCTION TO ENTOMOLOGY 



with its tip joined to the second anal vein near its base. On the hind 

 wings veins Sc+ Ri and vein Rg coalesce for a short distance near the 

 base of the wing ; vein AI2 may be either well preserved or much weak- 

 er than the other veins, or in a few cases lost ; and there is considerable 

 variation in the point of origin of this vein. 



Fig. 853. — Wings of Catocala fraxim. 



The majorit}^ of the larvas are naked, of dull colors, and provided 

 with five pairs of prolegs. As a rule they feed on the leaves of plants, 

 but some are borers and some gnaw into fruits. Among them are 

 some of the more important insects injurious to agriculture. 



The family Noctuidas has been divided into many subfamilies. 

 In the following pages the more important of those represented in 

 our fauna are briefly discussed, in order to show, as well as possible 

 in a limited space, the variations in form included in this family, and 

 to indicate the position of our more important species 



