128 Mr. G. C. Champion's Revision of the Mexican 



Group ICHTHYURINI. 



This group may be characterised thus : — Apical joint of 

 the maxillary and labial palpi stout, securiform or cultri- 

 form; prothorax subquadrate, entire; elytra greatly 

 abbreviated, leaving the wings in large part exposed; 

 abdominal segments 1-8 each with a small circular orifice 

 at or beneath the outer apical angle {Ichthyurus, etc.), 

 the orifice in 1-7 sometimes placed at the tip of an oblique 

 tubuliform process arising from the space between the two 

 surfaces {Maronius and Belotus), 8 forcipiform or bilobed 

 in one or both sexes ; genital armature asymmetric ; tarsal 

 claws lobed or toothed at base, or simple, uncleft at tip. 



The following known genera belong here : — Ichthyurus, 

 Trypherus, Lobetus, Maronius, and Belotus. The circular 

 orifice at or near the tip of each process of the chitinous 

 eighth dorsal segment of the abdomen is conspicuous in 

 all these insects, but that on each side of the preceding 

 segments (except in Maronius and Belotus) is often hidden 

 beneath the lateral fold in dried specimens. The genital 

 armature of Maronius and Belotus is very similar to that 

 of the Chauliognathinae. 



Ichthyurus. 



Ichthyurus, Westwood, Cabinet Orient. Ent. p. 83 (1848); 



Lacordaire, Gen. Coleopt. iv, p. 361. 

 Biurus, Motschulsky, Etudes Ent. i, p. 13 (1853). 

 Diurus, Gemminger et Harold, Cat. Coleopt. vi, p. 1684 



(1869). 



Various Eastern Ichthyuri are now known with the femora 

 and tibiae simple in the two sexes, as in certain Tropical 

 American forms, and these latter cannot therefore be 

 separated from Westwood's genus. The stout, vertical 

 head, the very large, oval or reniform, somewhat narrowly 

 separated eyes (as seen from in front), between which the 

 antennae are inserted close together, the forcipiform or 

 bilobate eighth dorsal segment of the abdomen (usually 

 differing greatly in form in the two sexes), and the feebly- 

 developed asymmetric genital armature of the males, are 

 characteristic. Lobetus mirabilis, Gorh., from Mexico, its 

 extraordinary (^ antennae and maxillary palpi notwith- 

 standing, must be provisionally included in Ichthyurus, 

 the general structure of the head, abdomen, etc., agreeing 



