580 Mr. T. Vernon Wollaston on the 



103. TETHACOPTUS (nov. gen.). The present genus, the 

 type of which (although very much smaller, and more 

 lightly punctured) at first sight closely resembles Penta- 

 mimus, is remarkable for its quadriarticulate funiculus,- 

 it being the only instance amongst the entire Cossonida, 

 outside the subfamily Dryophthorides, so far at least as I 

 have hitherto observed, in which that organ is composed 

 of but four joints ; yet so unmistakeably is it a member, 

 as regards the whole of its other details, of the Rhyncoli- 

 form groups that it would be as absurd to remove it on 

 account of the structure of its funiculus into the Dryoph- 

 thorides (with which in everything else it totally disagrees) 

 as it would be to regard Pentamimus and Tomolips as 

 Pentarthrids, or to include Hexarthrum amongst the 

 Onycholipides. In point of fact there can be no question, 

 despite its 4-jointed funiculus, about its affinities ; and it is 

 a significant fact that the only exponents of the subfamily 

 Cossonides in which the funiculus is made-up (so far as I 

 am aware) of less than seven articulations should pertain 

 to genera which appear, in a natural system of arrange- 

 ment, to be at no great distance from each other, namely 

 Hexarthrum (in which the funiculus is composed of six 

 joints), Tomolips and Pentamimus (in which there are 

 but five), and Tetracoptus (where the number is reduced 

 to four). 



Apart however from the primary peculiarity to which I 

 have just called attention, Tetracoptus may be known by 

 its cylindrical body and very lightly sculptured surface ; 

 by its exceedingly short and broad, but nevertheless pa- 

 rallel, rostrum (which has a wide, but shallow, channel in 

 front) ; by its elongate, large, subconical prothorax (which 

 is about the same width posteriorly as the elytra, and is more 

 constricted in front than in Pentamimus):, by the small- 

 ness of its scutellum ; and by its abrupt, considerably- 

 developed club. Its anterior coxse are tolerably wide 

 apart, and the four hinder ones are about equidistant ; its 

 legs (especially as regards the tibiae) are somewhat short, 

 its third tarsal joint is simple, and its claws are minute. 



The single example of this genus from which my diag- 

 nosis is compiled has been communicated by Mr. Pascoe, 

 and was captured by Mr. Wallace at Dorey in New 

 Guinea. 



104. XESTODERMA (nov. gen.). The present genus 

 and the following one are a good deal allied to each other, 



