OF PHILADELPHIA. 393 



brown lines ; abdomen brown, witli a yellow vitta; dilated at tip^ 



Inhabits tbe United States. 



Length less than two inches. 



% Head greenish-yellow ; eyes distant above ; labrum with an 

 indented point in the middle ; between the eyes a black band, 

 including the stemmata and antennae; thorax greenish-yel- 

 low, with three double fuscous vittse; between the wings a 

 greenish-yellow vittae; wings immaculate ; costal nervure green- 

 ish ; carpus fuscous small, the transverse line of its base pass- 

 ing obliquely across the second series of cellules; accessory 

 membrane very small ; abdomen dark fuscous, cylindrical, thicker 

 at base, and much dilated at tip; a dorsal yellowish line, inter- 

 rupted by the incisures, wider on the basal segment, and ex- 

 hibiting a spot only on two of the dilated segments ; anal ap- 

 pendices four, short, subulate : sides of the abdomen with a di- 

 lated [17] yellowish vitta on the basal segment, on which is also 

 a lateral tubercle ; remaining segments with a spot on the base 

 of each, those on the dilated segments are much larger, that on 

 the terminal segment occupying all the side, yellow and conspi- 

 cuous ; pleura green-yellow, with two oblique, fuscous lines ; feet 

 fuscous : tibia with a dull green line ; the dilated tip of the ab- 

 domen is very concave beneath. 



9 Tubercles of the basal segment of the abdomen obsolete ; 

 abdomen at tip somewhat less dilated ; anal appendices two. 



Length two inches. 



Common in June, on the banks of the Wabash. 



It resembles ybrcTpa^a Fabr., closely, but the feet of that spe- 

 cies are yellowish above ; the dorsal line of the abdomen is capi- 

 tate on each segment, and on the basal segment trilobate. 



It belongs to the genus Gomphus Leach. 



10. ^.STIGMATA. — 9 Body yellow ; stemmata rather large; 

 thorax with a double brown arcuated vitta before, each side of 

 which is an abbreviated, oblique, brown line, and another brown 

 line on the suture of the pleura ; wings with a very slight tinge 

 of yellowish, at their origin ferruginous ; costal edge whitish, 

 with two series of minute black points ; stigma rather large, 

 blackish ; tergum, each segr^ent excepting the basal and ultimate 



1839.] 



