486 Mr. Gilbert J. Arrow on Characters aiid Relationships 



Two genera, Anaides and Chaetodus, placed together 

 in the Trogidac by Westwood, were separated by La- 

 cordaire, and the second transferred to the Hylosoridae. 

 Phaeochrooys, of Candeze, which has distinct affinities 

 with both these genera, and in which the fusion of 

 the ventral segments, regarded as characteristic of the 

 Hyhosorinae, reaches its maximum, is placed in the 

 Troginae on account of the number of those segments 

 externally visible. Liparochras again, which has the 

 faculty of folding the body so characteristic of the small 

 Troginae, has the antennal club of the very different 

 form found in the Hghosorinac, and the a,symmetrical 

 front claws of the male, which I believe are found in 

 no other Laparosticts except the Hybosorine genus 

 Phacochrous, also occur in Liparochrns. It is obviously 

 unnatural to interpose between these closely-related 

 genera the great groups of Coprinae and Aphodiinae, 

 as proposed by Erichson, or even the Geotrupinae, as 

 Lacordaire has done, and indeed in my opinion it is 

 impossible to refer them to different sub-families. 



The genus T7'ox is a peculiar and rather isolated one 

 which, except in the form of the abdomen and elytra, has 

 few points of resemblance to those mentioned above. 

 In the structure of the head, antennae, organs of the mouth, 

 prothorax, scutellum and legs it is entirely different. Its 

 only near ally is Gry2')togenius, a genus with a slight 

 superficial resemblance to Anaides, of which the second 

 known species is described at the end of this paper. The 

 essential characters of the Troginae are also found in the 

 curious contractile-bodied group of the Acanthocerini. 

 The following genera, which have been assigned to the 

 Troginae, I propose to transfer to the Hyhosorinae, viz. 

 Liparochrns, Anaides, Phaeochroops, Phaeochriditts and 

 Pantolasius. 



These two sub-families are most easily grouped according 

 as (1) the antennal club is simple, the head more or less 

 angular in front, and the labrum and mandibles not ex- 

 tended horizontally (Troginae) ; or (2) the joints of the 

 antennal club are cup-shaped and telescope one within 

 the other, the head quadrate or elliptical in front, and 

 the labrum and mandibles horizontal, flattened and 

 plainly visible from above (Hyhosorinae). 



In the Troginae the first joint of the antenna is 

 greatly enlarged, more or less bent, and usually projects 



