20 NEUROPTERA OP NORTH AMERICA. 



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

 Hob. Mexico. The unique type is vei'y 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, labrura 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.? 



Nab. Ohio River, Pittsburg ; "common in May." Say. 



Unknown to me. 



9. P. Coulonii. 



Perla Coulonii Pictet, Pe$l. 212, 22 ; PL x, fig. 4. Walk. Catal. 150, 32. 



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

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

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

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



Length to tip of wings 46 millim. Alar expanse 7t 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 



