PSE UDOXE CROP 7 ERA . 



/ 



ures only 6 mm., and the tarsi are very long. These two species are our most 

 common representatives of this division of the Gomphinse. 



CORDULEGASTERIN/E. — Our only genus is Cordulegaster, of which but few 

 species are found in the United States. 



Cordulin.e. — We have three genera of this sub-family, each of which is 

 well represented in our fauna. These are Macormia, Epitheca, and Cord&lia. 



LibelluliN/E. — This sub-family is represented in our fauna by at least ten 

 genera. 



Family III. — Perlid^E.* 



Order PLECOPTERA of some authors.f 



(Stone-flies?) 



The family Perlidce includes comparatively few species ; but 

 members of it are common about any of our creeks. These insects 

 are called Stone-flies because the immature forms are very abun- 

 dant under stones in the bed of streams. The adults are found fly- 

 ing about or resting upon herbage in the vicinity of water. 



The body is depressed, elongated, and with the sides nearly par- 



Fig. 72. — Ptcronarrys regalis. 



allel (Fig. 72). The prothorax is large. The antenna? are long, 

 tapering, and many-jointed. The wings are unequal, the second 

 pair being the larger, and lie upon the abdomen when at rest. The 

 tarsi are three-jointed ; and in most species the caudal mid of the 

 abdomen is furnished with two setae. 



* Perlidre, Perl. 1 : a proper name. 



f Plecoptera: plecos {nXeKoi), plaited; pleron (itrt <<<"'), a wing. 



