318 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



PERLA VERTICALIS, sp. nov. 



TYPE. M. C. Z. 10,815. N. H.: Franconia (Mrs. A. T. Slosson). 



Brown; most of lower face and most of vertex back of ocelli pale yellowish 

 and even between posterior ocelli, only sides of head back of eyes dark; a 

 median pale stripe on the pronotum, broader in front; ventral plate of female 

 pale; legs and antennae pale brownish; wings nearly hyaline, veins brown; 

 radial sector two-branched, six median and cubital cross- veins; anastomosis 

 continuous. Posterior ocelli much nearer to the- eyes than to each other, 

 ocellar triangle broader than long; lateral bosses about as near antennal ridges 

 as to the posterior ocelli; pronotum one and one half broader than long, sides 

 nearly parallel, front and hind margins both convex; female ventral plate very 

 large and long. 



Expanse 30 mm. 



Near to P. modesta of Colorado, but it is smaller and the ventral 

 plate much longer. 



PERLA INCESTA, sp. nov. 

 TYPE. M. C. Z. 10,838. Oregon (Hagen coll.). 



Brown; in general similar to P. varians, P. similis etc. in having a narrow 

 median stripe of pale on the pronotum, and a pale median spot on top of the 

 head, and a pale' spot each side on lower face; abdomen brown, pale on venter 

 near tip, setae and legs pale. Wings also similar to these species, nearly 

 hyaline, with yellowish venation, radial sector three-branched, three cross- 

 veins beyond end of subcosta, latter ending at anastomosis, latter disjointed, 

 six to eight median and cubital cross-veins, first anal vein strongly sinuate' 

 just beyond the anal cell. The posterior ocelli are nearly twice as near to eyes 

 as to each other, the ocellar triangle almost twice as broad behind as long; 

 lateral bosses small and as close to antennal ridges as to posterior ocelli. Pro- 

 notum one arid one fourth broader than long, sides nearly parallel. 



Expanse 30 mm. 



It differs from all the related forms in the shape of the ventral 

 plate which is nearly straight across at tip with a distinct median 

 emargination. 



PERLA ANAMENSIS, sp. nov. 

 TYPE. M. C. Z. 10,830. Anam (Frustorpher). 



Pale yellowish, a large black spot over the ocellar area; pronotum and rest 

 of thorax rather brownish; wings nearly hyaline, veins yellow; legs pale, 

 femora tipped with dark. Ocelli large, posterior ocelli plainly closer to each 



