1878.] 601 {LeConte. 
coxe are also conical, prominent and contiguous. The antenne are slen- 
“der and longer than the head and thorax, as in the true Lathridii with cos- 
tate prothorax. These differences in structure entitle it to be ranked as a 
distinct genus for which the name Stephostethus may be adopted. 
The two following species belong to Hnicmus, though the 
antenne are more slender and a little longer than in those 
above described, and the sides of the prothorax are flattened. 
25. Lathridius tenuicornis. Robust, depressed, dark brown, 
head and prothorax opaque, scabrous, slightly channeled. Prothorax more 
than one-half longer than wide, narrowed before and behind, sides strongly 
rounded, oblique towards the base, margin finely serrate, flattened but not 
reflexed ; disc with a transverse slightly curved impression in front of the 
base, extending nearly to the sides. Elytra oval, wider than the prothorax, 
strongly margined, impressed near the base, shining ; strize scarcely impress- 
ed, finely punctured, interspaces flat, each with an obsolete row of very 
fine points. Antenne shorter than the head and prothorax, slender, three 
outer joints longer, but very slightly thickened. Length 2 mm.; .08 inch. 
California, near Sonoma. 
26. Lathridius laticollis. Less robust, sub-depressed, brown, an- 
tenn, legs and antennee rufous. Head and prothorax opaque, scabrous, 
feebly channeled, the latter nearly twice as wide as long, formed and 
sculptured as in L. tenutcornis, but less rounded on the sides. Elytra 
elongate-oval, very little wider than the prothorax, truncate at base, 
strongly margined at the sides, slightly impressed near the base ; strie 
punctured, scarcely impressed, fainter behind ; interspaces nearly smooth, 
flat. Antenne two-thirds as long as the head and prothorax, slender, 
outer three joints a little thickened. Length 1.5 mm.; .06 inch. 
Detroit. This species is very closely related to L. tenui- 
cornis, and differs only by the prothorax being less rounded 
on the sides, and the elytra but little wider than it. 
ODONTOSPHINDUS nov. gen. SpHiInDIDé. 
General characters as in Sphindus, except : 
Body elongate, glabrous; sides of the prothorax but feebly rounded, 
with 6 or 7 distinct teeth ; elytra with strive not impressed but strongly 
punctured. Flanks of prothorax not concave for the reception of the an- 
tenne. Antenne, legs, tarsi and sterna precisely as in Sphindus. 
This genus would seem to indicate a relation between the families Sphin- 
didze and Derodontide. 
27. O. demticollis. Elongate, sub-cylindrical, brown, glabrous. 
Head finely punctured, transverse frontal impression deep, vertex, with a 
broad but not deep channel. Prothorax twice as wide as long, slightly 
narrowed in front, strongly but not coarsely punctured, sides nearly 
straight (1), or slighthly rounded (2), with 6 or 7 distinct teeth, hind 
PROC. AMER. PHILOS. SOC. xvir. 101. 83w. PRINTED JUNE 11, 1878. 
