442 Mr. G. J. Arrow on the Oriental Members 



Sumatra (D. crassa, Sharp) and placed it in another Hop- 

 liine genus, Dichelhoplia, and Pairmaire in 1898 followed him 

 by adding a species from Tonkin to that genus (D. fusco- 

 picta). Dalla Torre's recent Catalogue of the Melolonthinse, 

 while naturally omitting these errant forms, has collected 

 nine in all under the name Dichelomorpha, but two of these 

 (the " Plectris " punctuligera and glabrilinea of Walker) have 

 certainly no connection with it. I have referred to these 

 in my paper on the " Melolonthine Beetles of Ce3'lon " 

 (Ann. & Mag. Nat. Hist. (8) xviii. 1916, p. 430). 



But this does not exhaust the errors of which these insects 

 have been the victims, for a genus, Diphycerus, formed by 

 Fairmaire for two species from China and placed by him in 

 still another section of the Melolonthime, proves upon 

 examination to be closely related to Dichelomorpha. Of 

 this genus I have here described three additional species and 

 a third Oriental genus is also characterized. 



The genus Dichelomorpha will certainly prove to comprise 

 very numerous forms. A few of those contained in the 

 British Museum are here named and described. It is 

 possible that others than those I have mentioned may 

 have been wrongly ascribed to other genera, but I have 

 appended a list of all at present known to me. These 

 insects have in common a number of peculiar features, 

 chief of which are the mobile but symmetrical claws, 

 those of the front feet generally differing a little from the 

 rest, and the remarkable interlocking of the pronotum and 

 scutellum, the base of the former being notched on each 

 side, sometimes deeply and sometimes only minutely, to 

 receive the anterior angles of the scutellum, which is some- 

 times also notched in the middle to receive a median process 

 of the pronotum. Diphycerus differs from Dichelomorpha in 

 having this interlocking mechanism much more strongly 

 developed, as well as in its very sharp and slender claws, 

 which are cleft upon the front feet alone. 



A marked characteristic of the group is the great dis- 

 parity between the sexes. The females have sometimes 

 little resemblance to the males and are generally less 

 numerous. In the male the legs are generally very stout, 

 the abdomen short and hollowed beneath, with the ventral 

 segments free and the pygidium rather long and narrow. 

 In the female the legs are comparatively slight and feeble, 

 the abdomen is large, rotund and rigid, and the pygidium 

 short and broad. In some species of Dichelomorpha the 5th 

 ventral segment is enormously enlarged in the female and 



