256 NATHAN BANKS. 



Perla illustris n. sp. — Head dull black, with a large jiale yellow spot 

 each side behind, above eyes and reaching medially to the posterior ocelli, basal 

 joint of antennse black above and beneath, second joint wholly pale, rest black- 

 ish ; pronotum uniform dull black, thorax mostly black, one or two pale spots on 

 each side of the mesothorax ; sternum black; coxse yellow; legs pale, femora 

 lined with blackish ; abdomen brownish-black, the segments above margined 

 with pale behind ; setas wholly black. Wings pale, rather yellowish, with mostly 

 ■ yellowish venation, the subcosta and the radius brown on basal half, the radial 

 sector also partly brown. The male is similar to the female, but the venter is 

 yellowish and with three rows of black spots; abdomen above pale yellow on 

 basal part, beyond more reddish-yellow, setse wholly black. In female the ven- 

 tral plate is strongly produced in middle, more so than in allied forms (P. tristis. 

 P. Jlavescens, P. capitata, etc.). In the male the superior appendages are recurved 

 as in allied forms, but the fifth segment is not as much prolonged and has a 

 broader tip than allies. Expanse, 9 , 36 mm. ; "J, , 28 mm. 



From Mont St. Hilaire, and Montreal, Canada, July. 



Differs from allies of this section {Marthamea Klap.) of Perla in 

 genitalia; from P. capitata and P. media in dark setxe, and from 

 others in paler wings. 



Perla excavata n. sp. — Head yellow, a transverse brown mark over pos- 

 terior ocelli, extending forward and dividing behind the anterior ocellus, each 

 branch extending outward to a stripe at base of antenn£e ; clypeus black in mid- 

 dle, basal joint of antennse black, rest yellowish; pronotum brown, rugulose, 

 plainly broader than long, sides parallel, barely tapering behind, thorax brown ; 

 abdomen yellow-brown, paler beneath, setae yellow at base, beyond brown ; legs 

 yellow-brown, tips of femora and tibise blackish, the tarsi also dark. Wings 

 gray-hyaline, venation brown, radial sector forked three times beyond the anas- 

 tomosis. Length to tip of wing 30 mm. 



Chain Bridge, Virginia, June 9th. 



The species allied to P. excavata are the following: 



Perla fuiiiosa Banks. 



From Virginia and North Carolina; a square black spot over 

 ocelli ; wings brownish ; ventral structure similar to P. couloni, but 

 a very much smaller species, and with wings much darker than any 

 of this group. 



Perla lurida Hagen. 



I do not have this species; from a sketch made from the type, 

 the ventral plate is similar to P. couloni, but from the description it 

 is probably distinct. 



Perla couloni Pictet. 



Our lai'gest species ; 1 have it from New York and Michigan. 

 The spot over ocelli is rather broad in front and concave, not ex- 

 tending toward antenna; wings grayish, venation brown. 



