Staplii/linidce of the A}iiazun VnUeij. 387 



HOLOTROCHUS. 



Six species are at present placed under this generic 

 name, five of whicli inliabit tropical America, the other 

 being found in jNIadagascar. I here describe six other 

 species ; of these the //. durus appears to be somewhat 

 allied to the H. volvulus figured by Erichson. The 

 species I have described as H. syntheticus differs from 

 the //. durus by some structural peculiarities, among the 

 more interesting of which is the formation of the apical 

 segments of the hind body. Attention being paid to this 

 character and to the facies of the species an affinity with 

 Lispinus is strongly suggested. The other two species, 

 viz., H. pubescens and H. suhtilis, Avhen I first examined 

 them, at once suggested to me a relationship with an insect 

 Avhich has been one of the unsatisfactory ones in the clas- 

 sification of the StapliylinidcR, viz., Phloeocharis subtilis- 

 sima ; and, on comparing the //. puhesceiis with P. sub- 

 tilissirna, 1 find such a prima facie resemblance in the 

 structure of the thorax and middle body as to lead me to 

 think that the natural connection of Phlceocharis subtilis- 

 simn will be found to be Avith this group of Holotrochus. 

 Indeed, I may say, the variety of facies and of certain 

 structural characters which exist in Osorius and its allies 

 and in these species of Holotrochus, suggest to me that 

 the accurate study of these insects will be found to suggest 

 an improved arrangement of some of the Piestini, Oxy- 

 telini and Phloeocharini ; and I shall not be at all surprised 

 if it be ultimately considered that we have here preserved 

 for us some of the more primitive forms of the Stapliy- 

 IhiidcB. It will not improbably be suggested that I ought 

 to have established a new genus for H. syntheticus and 

 //. jjubescens, but after the examination of several un- 

 described intermediate American forms which exist in my 

 collection, I have considered it better not to do so. As 

 regards the two last species here described, viz., H. clavipes 

 and H. Fauveli, I think it highly probable that they will 

 prove to be closely allied to Ancceus meyaceplialus, Fauvel. 

 In establishing the genus AnccBus, ]\I. Fauvel, to dis- 

 tinguish it from the 0.r?/^e/?7i?', pointed out the hidden and 

 retractile 7th segment of the hind body. The structure 

 of that segment is, however, subject to so much variation 

 both in the Oxytelini and Piestini (as they are at present 

 limited) that this point throws but little light on the 

 affinities of M. Fauvel's insect. M. Fauvel considered 



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