68 Trans. Acad. Sci. of St. Louis. 



at their own length from the base, the sides behind them strongly con- 

 vergent and evenly, circularly rounded to the neck, the base rather nar- 

 rowly truncate ; prothorax slightly narrower than the head, somewhat 

 elongate, the sides rounded anteriorly, becoming thence parallel and 

 straight in the male, or feebly convergent and slightly arcuate in the 

 female, to the rounded basal angles ; elytra large, quadrate in the male 

 or very slightly longer than wide in the female, a half to three-fourths 

 wider and two-fifths longer than the prothorax, parallel, with the sides 

 nearly straight, the basal angles very broadly exposed at base and only 

 narrowly rounded, the punctures only moderately coarse and unusually 

 sparse; abdomen much narrower than the elytra in the male but nearly 

 as wide as the latter in the female. Male with the fifth ventral unmodi- 

 fied, the slit of the sixth not more than twice as deep as wide, with its 

 sides parallel and nearly straight posteriorly, becoming oval anteriorly, 

 the edges finely beaded and the surface throughout beyond the bead 

 narrowly and feebly impressed ; sixth ventral of the female broadly and 

 very feebly impressed along the middle. Length 4.0-5.1 mm.; width 

 0.9-1.0 mm. California (Yuma) and Arizona (East Bridge), ustns Lee. 



I found this species in enormous numbers in hoof prints 

 partially filled with decomposing vegetable matter, in the 

 sands of the river bank on the Indian reservation opposite 

 Yuma, Arizona. A few species of Leucopaederus occur also 

 in Mexico, one of which has been described by Dr. Sharp. 



Lathrobia. 



The distinguishing characters of this, the largest subtribe 

 of the Paederini, are the abbreviated prosternal intercoxal 

 piece, and the strongly dilated anterior tarsi, which it pos- 

 sesses in common with the Dolicaones and Paederi, and the 

 conical and generally pointed or aciculate fourth joint of the 

 maxillary palpi, by which it differs from both of those sub- 

 tribes. Otherwise there is great variety in structure and 

 facies, from the impunctate and polished Dacnochilus, to the 

 densely and confidently sculptured Domene, and, in size, from 

 the larger forms of Glyptomerus and Eulathrobium to the 

 diminutive Lathrolepta. The eyes are present and generally 

 moderately developed, except in Glyptomerus , where the 

 normally faceted eye is replaced by a small whitish area in 

 which the chitinous integument is evidently very thin, un- 

 doubtedly conveying a general impression of light to the 

 cephalic ganglia and homologous with the smaller whitish 



