96 GEO. H. HORN, M. D. 



wider than loug, slightly narrowed in front, anterior angles obtuse, sides arcuate, 

 the margin crenulate, hind angles well defined, obtuse ; base aj-cuate with dis- 

 tinct marginal line; disc convex, with four very indistinct transverse ridges, the 

 first entire, the others interrupted by a rather broad and deep median depression, 

 surface otherwise granulate. Elytra as wide as the thorax, humeri distinct, not 

 dentate, disc striate, strige indistinctly punctured, the intervals flat with the inner 

 side feebly crenate, each interval on the outer side with a row of very indistinct, 

 elongate, flattened tubercles. Mesosternum opaque, densely punctured, not cari- 

 nate between the coxae. Metasternum smooth. Abdomen nearly smooth, a row 

 of coai'se punctures across the middle of each segment. Posterior femur elon- 

 gate oval, an indistinct marginal line extending nearly the entire length, the 

 tibia not stout, without oblique ridges, but with the usual triple series of acute 

 tubercles, spurs slender, the tarsus three-fourths as long as tibia, the first joint 

 elongate triangular. Length .14 inch ; 3.5 mm. 



This species has somewhat the facies of Rhysseiiius, and is placed 

 in the present genus from the form of the posterior tarsi. An ex- 

 amination of the maxillae will be necessary to define its position with 

 certainty, but with the material at hand that is not possible. The 

 thoracic and elytral sculpture distinguish it from quinqueplwatiis. 



Occurs in the Middle States, Dacota and Texas, but rare. 



Ps. nanus DeGeer. — Moderately elongate and convex, brownish, head and 

 thorax often piceous, shining, legs pale. Head coarsely rugulose, slightly verru- 

 cose in front. Clypeus broadly triangularly emarginate, the angles each .side ob- 

 tuse, sides feebly arcuate, gense obtuse. Thorax one-half wider than long, not 

 narrower in front, the anterior angles obtuse, margin not crenate, sides feebly 

 arcuate, hind angles very obtuse, base arcuate, the marginal line deep, disc con- 

 vex, transverse impression at the fi-ont angles, another at middle of declivity, a 

 slight median depression at base, surface with very coar.se and deep, sparsely 

 placed punctures, near the sides smooth. Elytra as wide at base as the thorax, 

 humeri distinct, not dentate, disc deeply striate, stripe punctulate, intervals con- 

 vex smooth, crenate on their inner borders. Mesosternum opaque, punctulate. 

 Metasternum smooth. Abdomen almost entirely smooth, the segments crenate 

 in front. Posterior femora smooth, the marginal line short, the tibise relatively 

 slender, the anterior and posterior edges serrulate, the outer face smooth, spurs 

 slender, subacute at tip, the tarsi as long as half the tibiie, the first joint elongate 

 triangu'lar. Length .8-. 10 inch ; 2-2.5 mm. 



This species is certainly the smallest lamellicorn in our fauna, and 

 Baron Harold says that it is probably the smallest known. Its oc- 

 currence in our fauna was first indicated by Harold (Stett. Zeit. 1867, 

 p. 282), but specimens were not known to me at the time of my 

 synopsis. 



Appears to be widely distributed, Harold records it from Chili, 

 Mexico and Cuba ; in our countiy I have seen specimens from Mas- 

 sachusetts (Blanchard), Texas, Arizona, California and Michigan 

 (Schwarz). 



