6 bulletin: museum of comparative zoology. 



Perlidae. 

 Perla innota, sp. nov. 



Type — M. C. Z. 10,045. N. Y. : Ithaca, 8 July. N. Banks. One 

 specimen. 



Face marks and antennae like P. iUustris, also the thorax and legs 

 marked about the same; the abdomen above is nearly wholly yellow, 

 the last segment is darker, but with pale apical margin except a median 

 deep black spot; setae black. Wings hardly discolored; venation quite 

 dark, except costal cross-veins. Anastomosis disjointed, the radial 

 sector beyond is twice forked; about five median and eight cubital 

 cross-veins; branches of anal cell wide apart at base. Related to P. 

 iUustris, but the female ventral plate (Plate 2, fig. 18) is more pointed, 

 with a notched tip, and convex sides, and shows two dark spots. 



Expanse 44 mm. 



Perla titusi, sp. nov. 



Type.— M. C. Z. 10,046. Idaho: Blackfoot, 22 June. E. G. 

 Titus. One specimen. 



Brown; yellow median spot on vertex, connected to median stripe 

 over pronotum, setae yellow at base; antennae brown, palpi dark 

 brown; legs yellow-brown, tarsi darker. Ocelli form a triangle more 

 than twice as broad as long, lateral ocelli much nearer eyes than to 

 each other; lateral bosses small, transverse, nearer to lateral ocelli 

 than to the eyes. Pronotum not one fourth broader than long, sides 

 parallel, angles square, moderately rugose above. Wings lightly 

 infumate, venation yellowish brown; radial sector three-branched 

 beyond anastomosis, the latter continuous, not disjointed; three or 

 four cross-veins beyond end of the subcosta, about eight before, about 

 eight median and cubital cross-veins; radial sector geniculate at 

 origin, branches of anal only slightly curved, and as far apart at base 

 as one half length of outer side of anal cell; outer part of cubitus 

 gives off' two branches. Ventral plate (Plate 2, fig. 25). 



Expanse 35 mm. 



Alloperla infirma, sp. nov. 



Type.— M. C. Z. 10,047. Colo. : North Boulder Creek, 22 August; 

 Florissant, 30 August. S. A. Rohwer; Grant, 20 August. E. C. 

 Jackson. Seven specimens. 



