Coleopterological Notices, III. 35 



abruptly so near the base which is much wider than the apex ; disk widest at 

 basal third, with a few fine, widely dispersed punctures toward the sides only. 

 Seutellum small, rounded, densely flavo-pubescent. Elytra three times as 

 long as the prothorax, and, at the base, one-fourth wider; sides feebly con- 

 vergent and nearly straight from the humeri to apical fourth or fifth, then 

 gradually more strongly convergent to the apex, each elytron being narrowly 

 truncate, the truncation bisinuate and limited internally and externally by a 

 minute acute dentiform process, which is not sufficiently elongate to be termed 

 spinose ; disk rather finely but deeply, sparsely, evenly punctate throughout, 

 the punctures perforate and without trace of definite arrangement. Length 

 10.0 mm. ; width 2.5 mm. 



Texas. 



A single male, probably received from Mr. Dunn, and without 

 any more definite locality. It differs from lepidus in having the 

 entire prosternum in front of the coxae strongly depressed and 

 coarsely densely punctato-rugulose, with the exception of a wide 

 polished apical margin ; in lepidus this space is divided by a polished 

 longitudinal elevation, thus forming two depressed areas. Longi- 

 collis does not appear to be referrable to any of the described Mexi- 

 can species. 



XYJLOTRECHUS Chev. 



The species insignis of LeConte, is remarkable for its pronounced 

 sexual disparity. A few years since I took a series of six speci- 

 mens from some low alder-like trees near the banks of the Trinity 

 River, in Humboldt Co., California, which upon cursory examina- 

 tion seemed to represent a distinct species near insignis. Subse- 

 quently I received a number of specimens from other parts of the 

 State. 



The Humboldt specimens are uniformly pale in color, with the 

 prothorax large and transversely subquadrate, and the markings 

 indefinite and more or less confused with the ground color by dis- 

 persion of the pale hairs ; upon close study all of these specimens 

 prove to be males. The female, represented before me by three 

 perfectly homogeneous examples, is black, and has the prothorax 

 narrower and the markings always distinctly and abruptly limited. 



Although such striking sexual differences are unusual or alto- 

 gether unknown in our other species of this genus, it appears to be 

 a more common condition in the allied Mexican genus Ochraatbes 

 Chev., a seemingly undescribed species of which, represented in my 

 cabinet by a good series, having the markings suffused in the male 

 but distinct in the female. 



