ISOPTERYX. 31 



39. P. citrinella. 



Perla citrinella Newp. Proc. Linn. Soc. I, 388, 6. Newp. Trans. Linn. 

 Soc. XX, 540, 1. P. citrinella Walk. Catal. 169, 97. 



Pale luteous ; the head as wide as the prothorax, ocelli fuscous ; 

 antennae fuscous, pale at base ; prothorax not broader- behind, 

 luteous, subrugulose, the anterior margin and middle line blackish, 

 angles obtuse, sides incurved ; wings hyaline, veins pale. (From 

 the description of Mr. Walker.) 



Length to tip of wings(?) 13 millim. Alar expanse 23 millim. 



Hub. St. Martin's Falls, Albany River, Hudson's Bay (Barn- 

 ston) ; Nova Scotia (Redman.) 



Unknown to me. The description of Mr. Newport differs a 

 little : " antennse entirely black." The description of Mr. Walker 

 was drawn from the typical specimen. Is it an Isopteryx ? 



40. P. imbecilla. 



Sialis imbecilla Say, Godman's West. Quart. Kept. II, 165, 3. 



Pale green, immaculate ; head with three fuscous ocelli, antennae 

 rather obscurer, pilose ; prothorax transversely oval, rugulose ; 

 wings greenish-white. (Taken from the description of Mr. Say.) 



Length to tip of wings 9 millim. Alar expanse 16 millim. 



Hdb. Ohio. River at Cincinnati. Common in the middle of 

 May (Say). Unknown to me. Is it an Isopteryx ? 



ISOPTERYX PICT. 



Wings with the transverse veins rare, almost absent ; no basal 

 space to the posterior wings; palpi setaceous, last articulation 

 shortest. 



1. I. cydippe ! 



Chloroperla cydippe Newm. Mag. Nat. Hist. ser. 2, III. 88, 8. Pict. Perl. 

 317. Walk. Catal. 168, 88.-*-C%/. sulphurea Fitch! (Collection of 

 de Selys Longchamps.) 



Pale yellow, immaculate ; head hardly broader than the pro- 

 thorax, three black ocelli ; antennas nigro-fuscous, base pallid : 

 prothorax transversely oval, subrugulose, angles rounded ; feet 

 pale, tarsi nigro-fuscous; wings greenish-hyaline, veins pale. 



Length to tip of wings ^799 millim. Alar expanse <f 13 

 9 16 millim. 



