173 



ScutellHin moderate, obtusely triangular. 

 Elytra entire, generally rather acuminate posteriorly. 

 Wings, in E. marinns, deficient. 



Abdomen, apparently composed of eight segments, of which the three apical are 

 large and corneous, and the rest membranaceous ; 2-6 furnished with inflexed 

 lateral processes. 

 Prothovdx (PI. VI., C, fig. 2, a) with the prosterniim very small ; cpinicrnd and 

 cpiniera inconspicuous ; coxal cavities moderate, oval, not contingent, narrowly 

 inclosed in front and behind. 

 Pectus with the mesosterniivi (PL VI., C, fig. 2, d) moderate; episterna moderate; 

 epiniem rather large, humeral, not extending to the coxal cavities ; coxal 

 cavities large, rounded, and distant. 

 metasternum (PL VI., C, fig. 2, g) rather short, transverse, not extending to the 

 sides of the body, with the posterior margin between the coxse nearlj' straight ; 

 episterna large and broad, rather longer than the metasternum ; i'pi)nera long, 

 concealed by the epipleural folds of the elytra. 

 Venter composed of six segments, the basal segment large, the rest short, equal to 



each other in length, apical entire. 

 Legs generally long and very robust. 



anterior with the trochanters small, triangular; femora robust, simple; tibis 

 generally dilated ; tarsi four-jointed ; 1 and 2 robust, deeply bifid ; 3 minute ; 

 4 long, robust ; claws rather slender, denticulate at the base beneath. 

 intermediate like the anterior, but longer, with the tibiae more dilated and ciliated. 

 jMsterior like the intermediate, but much longer. 

 Cox(e anterior moderate, oval, and prominent, not contingent. 

 intermediate rather large, rounded, and distant. 



posterior large, subpyriform, not extending to the episterna, and widely distant 

 from each other. 



The genus Rlnjpobiiis was founded by Dr. Le Conte in 1852 upon a species 

 found in America, and described by him under the name of R. marinus in the 

 Proceedings of the Academy of Sciences of Philadelphia, vi. p. 141. In 1859 

 M. Duval published (Gen. Col. Eur. ii. p. 236) the description of his genus Moronillus, 

 containing one European species, M. ruficoUis, an insect evidently congeneric with 

 the K. marinus of Le Conte. Again, in 1854, in his Ins. Mad. j). 480, Mr. 

 WoUaston created the genus (Jlceosoma to receive G. velox, a species found in the 

 Atlantic Islands, and also congeneric with Ii. marinus. From this it is clear that the 

 priority of nomenclature belongs to Dr. Le Conte, and that his name must be 

 retained for the present genus. The three sjiecies already mentioned resemble each 

 other very closely in colour, but may easily be recognized by their size and 

 sculpture. All the other species are very distinct from these, and from each 

 other. 



In Rhgpobius the head is much less exposed than in Ortlioperus ; from that 

 genus it also differs in its eleven-jointed antenna, and in many anatomical charac- 

 ters, of which the extraordinary shape of the mandible is the most remarkable. 

 The mandibles of Rlu/pobius were so totally unlike those of any genus I had pre* 

 viously seen, that it was not until I had dissected many individuals that I became 

 convinced that they were true mandibles ; but since then I have discovered that 

 mandibles of precisely similar form exist in the genus Catopti/.r, and in some 

 others. 



