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 4.0-5.1mm.; width 
0.9-1.0 mm. California (Yuma) and Arizona (East Bridge). ustus Lec. 
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 confluently sculptured Domene, and, in size, from 
the larger forms of Glyptomerus and Hulathrobium 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 
