20 NEUROPTERA OF NORTH AMERICA. 



Length to tip of wings 18 millim. Alar expanse 35 millim. 

 Hab. Mexico. The unique type is very defective. 



a a Accessory subcostal veinlet of the anterior wings, two- 

 branched. Subgenus Perla Pictet. (Apical costal space with 

 some transverse veins.) 



8. P. dorsata. 



Sialis dorsata Say, Godman's Western Quart. Rep. 1823, II, 164, 1. 



''Black varied with rufous ; head blackish, with about six blacker 

 spots ; beneath pale yellowish, labruni pale ; palpi black ; pro- 

 thorax blackish, with impressed blacker lines, anterior and poste- 

 rior incisures and dorsal vitta rufous, angles rather prominent, a 

 pale obsolete line from the base of the thorax to the abdomen, be- 

 neath yellowish, disk of the segments black ; trochanters yellowish; 

 abdomen black, segments above with yellow posterior margins, 

 venter pale yellow ; nervures of the wings deep black." — Say 

 (amended, Uhler). 



Length to tip of wings 50 millim. (If inches). Alar expanse 

 80 millim.? 



Hab. Ohio River, Pittsburg; "common in May." — Say. 



Unknown to me. 



9. P. Coulonii. 



Perla Coulonii Pictet, Perl. 212, 22 ; PI. x, fig. 4\ Walk. Catal. 150, 32. 



"Black; head broad, the sides and occiput luteous ; beneath 

 luteous; the prothorax large, fuscous, very rugulose, the disk 

 obscurer ; abdomen paler fuscous ; setae rather short, fuscous ; 

 wings fusco-hyaline, veins fuscous, stout." — Pict. 



Length to tip of wings 46 millim. Alar expanse 11 millim. 



Hab. United States. Unknown to me. Perhaps P. dorsata? 



Is it different from Walker's species, captured at the " Macken- 

 zie and Slave Rivers ?" 



10. P. immarginata. 



Sialis immarginata Say, Godman's West. Quart. Rep. II, 164, 2. 



" Black varied with yellow, or yellow varied with black ; eyes 

 deep black-brown ; prothorax transversely quadrangular, posterior 

 angles a little rounded, disk a little rugose, with impressed irregu- 

 lar lines, an impressed dorsal line, and each side of it a slightly 



