164 THOMAS SAY FOUNDATION 



Perlinella drymo Newman. 



(Plate 24, figs. 6, 7. 8, !», and text fig. 7.) 



1839. Isogenus drymo Newman, Mag. Nat. Hist., 3:86. 



1852. Isogenus dry mo Walker, Cat., p. 146. 



1861. Perla drymo Eagen, Syn. Neurop. N. A., p. 19. 

 1863. Perla drymo Hagen, Stet. Ent. Zeit., p. 371. 

 1892. Perla drymo Banks, Cat., p. 341. 



1907. Isogenus drymo Banks, Cat. Nenrop., p. 11. 



1862. Perla elongata Walsh, Proc. Acad. Nat. Sei. Phil., p. 366. 

 1892. Perla elongata Banks, Cat., p. Mil. 



1907. Perlinella elongata Banks, Cat. Neurop., p. 12. 



1895. Perla trivittata Banks, Trans. Am. Ent. Soc, 22:313. 



1907. Perlinella trivittata Banks, Cat. Neurop., p. 12. 



1909. Perlinella trivittata Enderlein, Zool. Anz., 34:389. 



Length to tip of wings, male, 10.5-16 mm. ; female, 16- 

 19 mm. Expanse, male, 19-28 mm. ; female, 28-34 mm. 



General color brown ; head yellow with two blackish 

 spots; pronotum with two wide longitudinal yellow 

 stripes. 



Head a little wider than prothorax; yellowish with a 

 large black mark over the ocellar triangle, bounded in 

 front by the yellow frontal ridge and extending outward 

 toward the base of the antennae; another black mark on 

 the clypeus in front of the frontal ridge ; a small dark 

 area just behind the eyes; hind ocelli a little closer to the 

 eyes than to each other. Antennae blackish. 



Prothorax much wider than long, slightly narrowed 

 behind ; with a narrow, median, longitudinal dark line and 

 each side of this with a wide yellow longitudinal stripe, 

 narrowed before the front margin ; lateral margins dark 

 brown ; all angles rounded. Legs dark brown to blackish ; 

 coxae and trochanters luteous ; first and second tarsal 

 segments very short, subequal, third tarsal segment more 

 than twice as long as one and two combined. Wings sub- 

 hyaline to fumose; subcosta reaches to the cord or very 

 nearly so, usually without any costal crossveins before 

 the end of subcosta and from one to four costal crossveins 

 beyond the end of subcosta; three to four crossveins be- 

 tween first and second anal veins of f orewing ; hind wing 

 with a large anal area and with a series of cubital cross- 

 veins. 



Abdomen brown to blackish, usually lighter under- 

 neath. Cerci black, long and slender. 



Male. Ninth abdominal sternite produced, evenly 

 rounded behind and before the apex with a raised yellow 

 transverse knob or hammer; the area each side of the 

 knob excavated ; tenth tergite entire with the median 

 area somewhat depressed behind ; subanal lobes modified 

 into slender, pointed, fingerlike processes which recurve 



