ART. 19 REVISION OF THE USECHINI BLAISDELL. 13 



The species of the genus TJsechus may for the present be separated 

 in the following manner: 



KEY TO SPECIES OF USECHUS 



Elytral base without processes overhanging pronotal base; surface roughly 

 sculptured; elytral intervals in part obliterated by juxtaposition of the coarse 

 serial punctures. 



Form elongate, parallel, coarsely sculptured; seventh costa discrete, 

 rarely joining the fifth, ninth, or pseudomarginal costate interval 

 strongly tuberculate at side of apical elytral declivity; antennal funicle 



stout, eleventh joint wider then long lacerta Motschulsky 



Form relatively broader, much less roughly sculptured; costate seventh 

 interval joining fifth at tubercle on summit of declivity, tubercle long; 

 costate ninth interval simply angulate at side of declivity; antennal 



funicle stout, eleventh joint as in lacerta santaclarae, new variety 



Form small, relatively robust, less roughly sculptured; costate intervals 

 devoid of tubercles (type), or tubercles incipient; costate seventh 

 interval joining fifth at middle of elytra; antennal funicle less stout, 



eleventh joint scarcely transverse horni, new variety 



Form similar to nudeaius, relatively more robust, sides more arcuate, 

 much less roughly sculptured as in santaclarae; costate seventh interval 

 joining fifth at tubercle, the latter elongate; costate ninth interval 

 angulate at side of declivity; ninth and tenth antennal joints less 



transverse, club as long as wide trinitatis, new variety 



Elytral base with short processes overhanging pronotal base; elytral intervals 

 more or less distinct between the rows of punctures; costate seventh interval 

 joining fifth at tubercle, the latter round; costate ninth interval feebly tuber- 

 culate at side of apical declivity nucleatus Casey 



As a final test of the stability of certain characters it was found 

 that out of 26 lacerta Motschulsky, 20 had the costate seventh interval 

 discrete; in 4 that interval joined the fifth, while in 2, the seventh 

 was discrete on one side and joined the fifth on the other. 



In 10 specimens of Santaclarae, the seventh interval joined the 

 fifth in all except 1, in that one the seventh was discrete. In this 

 variety the tubercle of the seventh is elongate and ridgelike, while 

 in lacerta it is shorter and rounded. The differential characters 

 appear to hold in a series and differ no more than in other species, 

 subspecies, and varieties. 



There is no question regarding the specific distinctness of lacerta 

 and nucleatus. Typical horni is unique. Larger series are needed 

 for study. 



On account of the difficulty of obtaining Motschulsky's works it is 

 thought best to give his descriptions of the species involved in the 

 present paper as an addendum. 



