ENDOMYCHID^E 139 



in the high mountains of Colorado (Garland), and nowhere else, 

 is highly improbable, and yet the genus in typical representatives 

 seems to be very widely distributed. It is not mentioned in the 

 " Biologia " as occurring in Mexico. 



ENDOMYCHIM: 



The reasons for the separation of this family, together with Ero- 

 tylidse and the Coccinellidae, as a distinct group of Coleoptera 

 known as the Trimera and placed at the extreme end of the series, 

 were always obscure, and of recent years these families very properly 

 have taken their place among the Clavicornia. The tarsi are not 

 strictly trimerous in any of them. Even in Coccinellidse there is 

 always a pronounced node at the base of the last joint and this 

 node sometimes becomes apparently a free joint. The Endo- 

 mychidae are with us a rather small family of fungous-loving beetles, 

 frequently conspicuous in coloration and generally of wide distri- 

 bution. It is probable that the larger forms are pretty thoroughly 

 known, but among the very small species there is much yet to 

 discover and record. 



Rhymbomicrus n. gen. 



The type of this proposed new genus is the very minute species 

 standing in our lists under the name Alexia lobata Lee. In the 

 genus Alexia, as remarked by Gorham, the base of the prothorax is 

 straight and not medially lobed as it is in lobata, and it is impossible 

 to assign the species to Rhymbus, because of the complete absence 

 of the sublateral pronotal sulci. In some characters Rhymbomicrus 

 seems to approach the Central American genus Exysma Gorh., 

 especially the Mexican Exysma Itevigata, which is probably generic- 

 ally different from the Central American type named Exysma 

 parvida. The body in R. lobatus is evenly oval and strongly convex, 

 the curve of the sides of the elytra evenly prolonged by the sides of 

 the prothorax without break. The surface is apparently almost 

 glabrous, impunctate and devoid of any kind of sculpture, uni- 

 formly dark piceous in color and shining; parallel with the basal 

 thoracic lobe, and at a slight distance therefrom, there is a feebly 

 impressed line not extending laterally beyond the limits of the lobe; 

 there is no subsutural stria. The prosternal process is narrow 



