44 THOMAS SAY FOUNDATION 



This plate, rounded on its hind border, or trun- 

 cate or more or less trilobate, or even slightly 

 retuse, but never acutely notched in the middle ; 

 generally a little shorter than the segment is 

 at sides badia 



Pteronarcella regularis Hagen. 



(Plate 7, fig. 15; plate 8, figs. 3, 4, 5.) 

 1873. Pteronarcys regularis Hagen, Bull. Geol. Surv. Colo., p. 573. 

 1900. Pteronarcella regularis Banks, Trans. Amer. Ent. Soc, 26:242. 

 1917. Pteronarcella regularis Smith, Trans. Amer. Ent. Soc, 43:459. 



Male. Length to tip of wings 18 mm. ; expanse 32 mm. ; 

 tails 9 mm. 



Female. Length to tip of wings 23 mm. ; expanse 41 

 mm. 



General color dark brown, head and thorax almost 

 black, abdomen reddish brown with a series of light col- 

 ored knobs on the lateral margin. 



Head about as broad as prothorax. Ocelli form an isos- 

 celes triangle, posterior ocelli a little closer to each other 

 than to the eyes. The antero-lateral margins of the 

 frons raised. A black area covers the ocellar triangle and 

 extends over the entire clypeus except for two small light 

 areas near the sides, nearly opposite the anterior ocellus ; 

 labrum brown ; on each side of the ocellar triangle a 

 crowned yellow tubercle ; rear of head dark Drown ; on the 

 inner margin of compound eyes a broad yellow band 

 touching the round tubercles and connected by a narrow 

 transverse band behind the ocellar triangle. Antennae 

 brown, second segment about as wide as long; third seg- 

 ment half again as long as wide, fourth segment not long- 

 er than wide. Palpi brown with very short hairs, the seg- 

 ments each appearing multi-articulate due to numerous 

 irregular chitinous half rings. 



Prothorax dark brown, about half again as wide as 

 long, sides straight and parallel, anterior and posterior 

 margins evenly convex, front angles nearly square, hind 

 angles rounded ; the mid-dorsal yellow band is indistinct 

 in the middle with rather bright yellow areas at the ends, 

 and there is a very narrow yellow line laid on the mid- 

 lateral margin. Disc covered with indefinite, dark, raised 

 sculpturings. 



Meso and metathorax black, except for a triangular 

 lighter depressed area near the front margin of the meso- 

 thorax. Wings uniformly brownish, veins dark brown. 

 Legs brown, knees blackish ; femora at distal end with a 



