RUIN0T.METUS. 



43 



or less sparingly with fine pale-fuscous pubescence, of a black colour 

 throughout. 



Brazil. 



The only example of this species which I have seen (in the collec- 

 tion of Mr. Baly) has the joints of the antennas shorter, and the 

 whole length of the antennae very apparently shorter (in proportion 

 to its body) than is the case in R. cyaneus. We shall be right, I 

 think, in viewing this difference as sexual (the example of R. assimilis, 

 with the shorter antennae, being of course a female) ; and if this be 

 the case, we are able to gather further, by an inspection of the two 

 insects, that in no other respects do the sexes of this genus differ, either 

 in robustness of legs, or in the relative lengths of the posterior tibiae, 

 or in the comparative size of the body : it is possible, however, that 

 the male specimens may be found to have the transverse depression 

 on the elytra more distinct and less obsolete than the females. 



R. assimilis is readily separated from all its congeners (to many of 

 which it would seem, at first sight, to be very closely allied) by the 

 distinct striation as well as by the rich purple colour of its elytra. 



8. Rhiiiotmetus depressus. (Front, fig. 5.) 



B. oblongo-ovatus, robustus, subconvexus, antice attenuatus, punc- 

 tatus, cyaneus; capite elongato, longitudinaliter carinato, ad basin 

 ■punctato, nigro ; thorace ad apicem constricto, quadrato, angidis 

 anticis obsoletis et depressis, ad medium longitudinaliter subtiliter 

 striato, nigro ; elytris latis, subparallelis, ad medium oblique de- 

 pressis, striato-punctatis ; antennis robustis, jiliformibus, nigris ; 

 pedibus robustis, fusco-subpubescentibus, nigris, tibiis posticis 

 fuseo suffusis. 



Long. corp. 2-i lin., lat. 1^ lin. 



Oblong-ovate, robust, subconvex, attenuated in front, punctate, 

 shining, of a bright blue colour. Head transverse, produced in front : 

 from the angles of the labrum two oblique carinations extend to the 

 base of the antennae ; between these is a' medial longitudinal keel- 

 like ridge, which diverges slightly into two subparallel raised lines, 

 and then is further produced at right angles to the upper and inner 

 surface of the eyes ; the eyes are large, subglobular, situated at some 

 distance from the base of the head ; the base is deeply punctate : 

 black, glabrous. Thorax broader than the head, quadrate, and 

 constricted in front; the anterior angles much depressed and ob- 

 solete ; the sides marginate ; at the base there is no trace of a trans- 

 verse depression (as in R. assimilis and R. cyaneus) ; at the basal 

 angles there is an obsolete group of punctures, and (when viewed 

 obliquely) a faint medial longitudinal channel may be traced from 



