280 
Psyche 
[Dec. 
Occiperla gen. nov. 
Type : Isoperla pinta Frison. 
Head broad, behind eyes it at once slopes inward; 
median groove well developed; ocelli small, lateral boss 
about as far from hind ocellus as from base of antenna; 
femora with bristles among the shorter hairs ; maxillary 
palpi moderately short, second and third joints rather 
thick, fifth long and slender; antennae with moderately 
long joints, short hair, and minute sense hair near end 
of joint; pronotum much broader than long; cubito-anal 
cross-vein at end of anal cell; cubitus forks so both 
branches are at an angle with the base ; anal brace arising 
a little before base of anal cell, transverse, no distinct anal 
lobe. 
I have Occiperla pinta from Huntington, B. Col., and 
Cowichan Lake, Vancouver; there are at least two other 
species in the West, both with the area in front of an- 
terior ocellus wholly yellowish, one with a pale longi- 
tudinal streak in the ocellar area, the other with ocellar 
area covered by a triangular dark spot. 
Subfamily Isogeninae 
1. The anal lobe fairly large and long, ending beyond the 
lower end of anal cell; in hind wings a series of 
cubital cross-veins ; moderately large specimens 2 
The anal lobe very small or absent, and if present it 
ends before the lower end of anal cell; usually 
smaller species 3 
2. Ocellar area about as broad as long, or nearly so ; head 
extending some distance behind eyes and plainly a 
little swollen before sloping inward ; median groove 
nearly or quite reaching occipital line Isogenus 
Ocellar area but little if any broader than long ; head 
very short behind eyes, scarcely space for more than 
the inward slope; median groove not reaching the 
occipital line Hydroperla 
3. Hind ocelli far from hind border of head, not under 
a ridge, nor a shallow groove reaching laterally, but 
projecting a bit above surface, anterior ocellus 
almost as near each eye as to anterior margin of 
