Malaeodcrm Gentra Prionoceras and Idgia. 327 



upper posterior tibial spur is longer than the lower one. 

 I. Jlavirostris a.i\i\ one or two otluTs huve the tarsal claws 

 widened to near the middle, instead of at the extreme base 

 only, but there is no trace of a membranous lobe in any of 

 these insects. The numerous testaceous forms with the 

 head in part or eiitirely, and the apices of the elytra, black 

 have given me the greatest dilKculty in distinguishing the 

 species ; and it has been found impossible iu some cases to 

 separate them at all satisfactorily till the J -genital armature, 

 or the sixth ventral segment, has been examined. These 

 striH^tures have been dissected in nearly all the species of 

 which the males are represented in the collections before 

 me *. The tegmcn {se/isu Sharp and Muir) is furnished 

 with two elongate, digitiform or spoon-shaped lobes, convex 

 and almost smooth above, concave beneath, together forming 

 an open tube, the lower outer edge of each (lateral) lobe 

 being more or less ciliate or finely denticulate, and some- 

 times sinuate or emarginatc before the tij). The median 

 lobef ( = penis-sheath or :edeagus of some authors) consists 

 of a long, acuminate tube, usually curved downward at the 

 tip, but peculiarly shaped iu the two Aralnau forms here 

 described (cf. PI. XI. figs. 9a and 10a), the opening from 

 which the membranous sac or intromittent organ is extruded 

 being placed on the dorsal aspect at some distance before 

 the tip. The sixth ventral segment is normally triangularly 

 emarginate iu J , but in one species at least {cf. PI. Xll. 

 fig. 49 a) it is so deeply bi-excised as to appear trilobed. 



One or two species have the sutural angle of the elytra 

 strongly hooked or dentiform (cf. PI. XII. fig. 50), a character 

 peculiar to the ? , as in the American genus Astylus. 

 Figures of the J -armature of nearly all the species here 

 enumerated are given on the accompanying Plates. 



The " Prionoct-rides,'' forming a subtribe of the " Melv- 

 rides " of Lacordaire based upon Prionocerus and Idgia, 

 should be treated as a separate group or family of tlie 

 Malacodermata, distinguished by the emarginate eyes, the 

 single spur to the anterior tiljiie, the simple tarsi and claws 

 (the latter at most widened in their basal half), the more or 

 less curved or excavate eleventh antennal joiut, aud the 

 closely pectinate tarsal joints 1-3 of the male. 



• They have all been made by Mr. .4. Cant. 



t C/. Sharp and Muir, Trans. Ent. .Soc. Lond. 1912 and 1918. The 

 term '* penis-sheath " has been iised by me for this organ in a recently 

 published paper on the genus Astylun. 



22* 



