466 Goleoplei^ological Notices, VI. 



rujivenb'is in its longer form of body, coarser piuictiuition and 

 sparser and dual vestiture. The pale color at the elytral apex 

 ascends at the lateral margins to about the middle, gradually -be- 

 coming faint. 



The epipleiirii3 are flat, almost horizontal, polished, and very 

 remotely and almost imperceptibly punctulate and pubescent. 



TRIC ]IO( IIKOUS Motsch. 



Itijturo.somus ; Emmenotarsus Mots; Pristoscelis l^ec. (pars.). 



Within the broad compass which we are compelled to give it, 

 this genus is in all probability one of the largest of the North 

 American Coleoptera, its species occurring in unnumbered scores 

 in the extreme western regions of the continent, and especiall}- in 

 California, where it constitutes one of the chief arboreal elements 

 of the order. Its species differ much among themselves in size 

 and vestiture, but agree in having the appendages of the tarsal 

 claws well developed, equal, as long as the claws and attached to 

 them except in outer third or fourth of their length ; these ap- 

 pendages are of a gelatino-membranous texture, and subject to 

 malformation or distortion which is frequentl}' deceptive and 

 misleading, especially under low powers of amplification. The 

 species may be distinguished from Eudasytes and Asj^lates by 

 the structnre of the epipleurai, and from Listrus and its allies by 

 having the outer surftice of the anterior tibi^t — and of the others 

 to a less extent — beset with an irregular and partially double se- 

 ries of short stiff and widely spaced spinules. The bod}' maj- be 

 simply pubescent or have erect setae in addition, and may have a 

 dense thoracic fringe of short cilia as in Listrus; this regular 

 fringe is however generally wanting in those species which bristle 

 with long erect seta\ 



The sexual characters are usually quite distinct though only 

 rarely ver}' radical, but the sexes are nearly alwa^^s readil}^ differ- 

 ential)le. The male as a ruje has the head, and less frequently the 

 prothorax, larger, the antennre longer, and the elytra relatively' 

 shorter than the female. The abdominal characters are generally 

 feeble, the fifth ventral in the male being more or less evenl}'' 

 truncate, but in a singular exception described below under the 

 name sexualis, this segment becomes strongly modified, an ex- 

 ception quite as pronounced as that of Cistela brevis when com- 



