130 



INTRODUCTION. 



ii. Second joint of posterior tarsi short, about 

 equal to the third. 



1. Pronotum at base narrower thau the base 



of the elytra, with distinct longitudinal 



furrows IIelophorinje. 



2. Pronotum at base not narrower than the 



base of the elytra, without distinct longi- 

 tudinal furrows. 



A. Clypeus einarginate ; scutellum long, tri- 



angular ; anterior coxal cavities open 



behind Spercheinje. 



B. Clypeus truncate ; scutellum small and 



short ; anterior coxal cavities closed 



behind Hydejeninje. 



II. Posterior tarsi with the first joint elongate .... Sphjeridiin^e. 



Amphiops might with reason be separated as a separate subfamily 

 (Amphiopix^e), on the character of its completely divided eyes, 

 which are analogous to those of Gyrinus. 



The position of the Hydrophilid.e is doubtful. They certainly 

 exhibit a strong relationship towards the DYTisciDiE, and Sharp 

 (Cambridge Xat. History, vi, p. 21) places them after the G-yrinidje. 

 Some authors place them between the Clavicorxia and the 

 Lamellicorxia, while Ganglbauer places them at the end of the 

 old Clavicorn series immediately after the Heterocerid^e. This 

 he does, apparently, in order to separate them off from the pre- 

 ceding families ; in fact he is inclined to regard them as quite a 

 separate division (Palpicorxia). So far as the wing venation 

 goes they certainly belong to his Diversicornia, as the charac- 

 teristic loop is very distinct in Hydrophilus, etc. 



Family 55. HETEROCERIDiE. 



Head large, sunk in the thorax as far as the eyes, porrect or only 

 slightly deflexed, mandibles projecting; antenna* short, variable, 

 ten- or eleven-jointed with (usually) the last seven joints forming a 

 compressed serrate club ; anterior coxal cavities open behind ; elytra 

 completely covering the abdomen, which has five free ventral seg- 

 ments, the first of which is furnished with a siridulating organ in 

 the form of an elevated curved line r ubbed by the posterior femur ; 

 legs stout, spinose, adapted for digging ; tarsi four-jointed, with 

 delicate claws. 



This family consisted originally of one large genus, to which one 

 or two have been added since the publication of the Munich Cata- 

 logue. About 100 species are known, and they are widely dis- 

 tributed throughout the world ; the majority inhabit the Palsearctic 

 region, but some half-dozen occur in India and Ceylon, and species 

 have been recorded from Cuba and Australia. They are small 



