1922.] 159 



A NEW GENUS OP ISCHNOCEBA (MALLOPHAGA). 



BY JAMES WATEESTOK, B.D., D.SC, F.Z.S. 

 Assistant Keeper in the Department of Entomology, British Museum (Nat. Hist.). 



(Published by permission of the Trustees of the British Museum.) 



For some time past the writer lias been engaged in a critical study 

 of the Ischnocera occurring on Palaearctic grouse, in the course of 

 which it has become evident that one small group of these parasites, 

 whose members have been variously referred to Lipeurus, Niinniis, and 

 Goniocofes, really deserves separate treatment. 



This new genus, which is diagnosed below, is perhaps the most 

 characteristic of the grouse Ilallo^jluiga and, in the writer's opinion, 

 its included species will, Avhen more perfectly known, afford important 

 clues to the phylogeny of their host genera. 



Laqopoecus, gen. nov. 



Head ( <?, 5 ) hroad ; iu front of the trabeculae parabolic aud continucusly 

 circumfasciate, i. e. without indication of a clear linear antero-median 

 longitudinal interruption ; enlarged characteristically iuiiuediately behind the 

 eye with the sides thereafter reclined towards the rounded temples ; occiput 

 distinctly but rather sh alio wly concave ; upper surface (in fully adult examples) 

 uniformly chitinised except (a) a clear straiglit transverse suture about one- 

 sixth from the anterior margin and (6j a second, parabolic clear band or suture 

 (often indistinct) running back from the antennal fossae, not reaching the 

 occipit.al edge but flattened out and parallel witli the middle third of that line. 

 Ventral surface — the oral fossa anteriorly nearly parallel with the outline of 

 the head. Antennae without appendages, the first joint in the ^ larger and 

 stouter. Abdomen short and broad — sometimes as broad as long, sides of first 

 segment divergent posteriorly, bands on tergites 1-7 divided broadly ( 2 ) or 

 more narrowly (J) into oblong blotches. Pleurites, heads not deeply inserted 

 into the preceding segments, thickened but not complicated except for a more 

 or less developed upper branch. Genitalia, c?, basal phite slightly constricted 

 distally. Paramers not articulated basally but quite capable of being flexed 

 upwards and backwards, the apical and ventral hairs approximated. Mesosome 

 flat, solid, with three ventral hairs at each side. The elongate tubular penis is 

 free, with two hairs on each side basally. When not exerted the paramers 

 enfold the sides of the mesosome with the penis closely appressed beneath ; 5 

 vulva simple, transverse medianly. a little concave. 



Genotype, Nirmus cajneratus hjonet (1830), Type host, Lyrurtistetrix. 



This genus has affinities both with Lqjeurus Nitzsch (sens, str.) 

 and Degeeriella Neum. (sens. str.). It does not, however, include 

 forms like X.ipeuru& docoplioroides Piag., from which a careful 

 examination of the head should secure its separation. 



June 1922. 



