330 



^A^ INTRODUCTION TO ENTOMOLOGY 



the fore wings separates from radius gradually, the two forming a 

 sharp angle (Fig. 37 6b). 



This is the largest of the families, including a large portion of the 

 genera and species found in our fauna; fourteen genera have been 

 described from this region. 



Family NEMOURID^ 



In this and the following family the media of the fore wings 

 separates from radius abruptly, the two forming a blunt angle (Fig. 

 376c). In this family the second and third anal veins of the fore 

 wings coalesce for some distance beyond the basal anal cell, forming a 

 forked vein (Fig. 376c), and the cerci are vestigial. 



The family is represented in our fauna by nine genera. Our more 

 common representatives are small, dusky, and grayish species that 

 are found emerging throughout the spring of the year. 



Family CAPNIID^ 



In this family, as in the Nemouridae, the media of the fore wings 

 separates from radius abruptly, the two forming a blunb angle (Fig. 

 3,7 6d); but in this family there are in the anal area of the fore wings 



^•4+5 



Fig. 376^. — Wing of Capnia sp. 



only simple veins arising from the basal anal cell (Fig. 376(f), and the 

 cerci are well developed. This is a small family which is represented 

 in our fauna by only three genera. 



The members of this family that are most often seen are the little 

 black species of Capnia that appear on snow on warm days in the 

 latter half of winter and in early spring. The naiads of these live chiefly 

 in small brooks. 



