APPENDIX. 305 



tinguished from that species at once, by the nervures of the 

 wings being altogether destitute of coloured margins. 



3. B. alba. White ; vertex and anterior feet above 

 dusky. 



Inhabits Winnepeek river. 



Thorax shghtly tinged with pale yellowish-brown ; «w- 

 ^enoryee^ short, rather robust; 7iervures upon and near 

 the costal margin dusky. 



Length of the body 9 about half an inch. 



This insect appears in immense numbers. They rise 

 upon the wing in the evening, and their short existence in 

 the perfect state appears to be terminated before sunrise. 

 For a more particular account of this species, see the Nar- 

 rative. 



ASCALAPHUS, Fabr. 



A. A-maculatus. Wings with a white costal spot ; an- 

 tennae as long as the body ; tergum varied with black 

 and testaceous ; eyes with a suture. 



Inhabits Pennsylvania. 



Head and stethidium covered by long cinereous hair, 

 the latter part blackish, varied with pale testaceous ; la- 

 bruni honey-yellow ; antennsn as long as the body, dull 

 yellowish-brown ; incisures blackish, clavum oval, com- 

 pressed, blackish with pale incisures ; eyes large, promi- 

 nent, in the middle divided by an impressed line ; wings 

 hyaline with a milk-white reflexion, an opake snow-white 

 spot near the tip of the costal margin, nervures black ; 

 tergum testaceous, segments with a dorsal line and oblong 

 spot each side, black, terminal segments nearly all black ; 

 sides black, varied with testaceous. 



Length to tip of wings one inch and a hglf. 



