164 Mr. R. MacLachlan's Monograph of 



Family I. HEMEROBIID^. 



Antennce short ; composed of a number of little rounded 

 joints. Terminal joint of the j^cblpi cylindrical, generally 

 subulate. Ocelli usually absent (present in Osmylus) . 

 Wings sub-equal (except in one sex of Psectra) ; costal 

 veinlets mostly furcate; sub-costa and radius separated to 

 the apexj or [Osmylns and Sisyra) becoming there con- 

 fluent; suh-costal area with one, or several, transverse 

 veinlets ; radius starting from the sub-costa, close to the 

 base, and running parallel with it; emitting either one 

 (whence then arise the others) or all the sectors; gradate 

 veinlets generally in two series, the portion of the wing 

 between the inner of these and the base occupied with 

 few transverse veins, or (Osmylus) many; the margins, 

 and veins, and veinlets, ciliated. 



Body short ; the extremity of the abdomen in the male 

 generally provided with appendices. 



Legs short, slender; the ungues generally simple. 



Larva, mostly arboreal (aquatic in Osmylus and Sisyra) . 



The following are the British genera : — 



A. Ocelli present. Transverse nervules numerous. 



Osmylus.* 



B. Ocelli absent. Transverse nervules few. 



A. Radius becoming confluent with the sub-cos- 



ta. (PI. IX. fig. 3.) .... Sisyra. 



B. Radius and sub-costa separate to the apex. 



a. First sector emitting the rest. Posterior 



wings minute in one sex. (PL IX. fig. 5) . 



Psectra. 



b. All the sectors emitted from the radius. Wings 



ample in both sexes. 

 a. A recurrent veinlet at the base of the cos- 

 tal area in the anterior wings, forming 

 a small free cellule. (PL IX. fig. 6; PL 

 X. figs. 1, 5, 10, 11, indicated at a.) 

 * Apical margin excised. . Drepanepteryx. 

 ** Apical margin entire, bounded. 



f Normally not more than four sectors. 



Hemerobius. 



ft More than four sectors. . Megalomus. 



h. No recurrent veinlet at the base of the 



costal area. (PL IX. fig. 4.) Micromus. 



• In a general monograph of Plauipennia, Osmylus would form the 

 type of a distinct family — Osmylidce. 



