426 Transactions of the Society. 



my original arrangement, provisionally, and confine myself to 

 some observations on the genitalia of the group. 



The virga possesses one very well-marked peculiarity ; it is 

 invariably horseshoe-shaped, and, as there are a pair of them, 

 there are four orifices for the emission of the semen. In all known 

 Diplatyinse this is the case, though the shape of the virga is various, 

 and the metaparameres offer considerable diversity. 



Zacher's arrangement of this genus has the merits of boldness 

 and originality, but I am convinced that he has in some cases 

 failed to identify his species correctly. This is a very pardonable 

 mistake in this genus, where I often have considerable doubt in 

 identifying individuals of species of my own description. 



Dvplatys macrocephalus Beauv. 



This has always been regarded as a purely West African species, 

 but I cannot distinguish, by external characters, a fresh specimen 

 from Uganda, sent to me by Mr. Gowdey (PI. V. fig. 9). The 

 metaparameres are quite peculiar, being very strongly bowed, 

 with the apex produced into a sharp point. The virga is short, 

 and there is a denticulate pad. 



It is important to examine the parameres of West African 

 specimens to settle this question of identity, for the genitalia 

 figured by Zacher and attributed to this species are totally different. 

 Zacher's specimens are from Usambara, and he relies upon the 

 unreliable determination of A r erhoeff. It remains to be seen to 

 what species these figures should be attributed (PI. V. fig. 14). 



Diplatys conradti Burr. 



My original type is in poor condition, and the genitalia are 

 inaccessible, but I have examined these organs in a specimen, 

 also from the Kamerun, which I attribute hereto, and I find the 

 genital figured by Zacher as those of D. eethiops (PI. V. fig. 11). 



The D. conradti of Zacher is another species. I cannot admit 

 Zacher's sub-genus Verhmffiella, based on the length of the virga, 

 as we find this organ nearly as long in some Indian species closely 

 allied to forms with short virga. It is, in fact, only a specific 

 character. 



Diplatys riggenbachi Burr, and D. raffrayi Borm. 



Here the metaparameres are slender, and of a peculiar shape ; 

 the virga is short (PI. V. figs. 7 and 8). 



Diplatys sp. n. 



A very characteristic form of genitalia is seen in a species not 

 yet described, from Sappo, Kamerun, in the Berlin Museum. It is 



