442 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



rated, interspaces broad, flat or nearly so. Legs wanting. Length, 

 as preserved, 5.60 mm., in life somewhat greater. 



Described from one specimen. 



Type.- No. 2,473 M. C. Z. Florissant, Col. (No. 11,731 S. H. 



Scudder Coll.). 



At first sight, this insect resembles an Acmaeodera, but cannot 

 enter that genus on account of the distinct mesoscutellum and sepa- 

 rate elytra. Behind the mesoscutellum is a narrow wedge-like sclerite, 

 probably equivalent to the "second scutellum" of Chlamys, but there 

 is no way of determining whether it was visible during life of the fossil, 

 when the elytra were closed. A similar structure is seen in the Floris- 

 sant fossil which I described some time ago under the name Acmaeo- 

 dera schae/eri, but my figure of that species does not show the line 

 of division between the two parts. Ptosima gibbicollis, our common 

 North American representative of the genus, exhibits the same 

 arrangement in about the same proportions, but it is necessary to 

 open the elytra to see it. Since the size, form and sculpture of P. 

 silvatica are similar to those of P. gibbicollis, I have assumed them to 

 be congeneric if the lines are not too closely drawn. It will be better 

 to consider that both of the Florissant insects which I have described 

 under Acmaeodera (A. schae/cri and A. abyssa) belong rather to Pto- 

 sima, though they differ in sculpture of the elytra. 



AGRILUS PRAEPOLITUS, sp. nov. 

 Plate 3, fig. 7. 



Form only moderately elongate, less so as a fossil than in life on 

 account of crushing by pressure. Head large, transversely suborbicu- 

 lar, longitudinally finely striate anteriorly, occipital region minutely 

 closely punctulate. Antennae moderately serrate but very poorly 

 preserved. Pronotum, as preserved, flattened so as to increase the 

 apparent \\ idth which is equal to twice the length, apex broader than 

 the base which is distinctly bisinuate, sides rather weakly arcuate, 

 front angles prominent, the left hind one with a strong arcuate carina. 

 Surface not very coarsely but deeply punctured, the punctuation close 

 and transversely confluent so as to form a reticulate pattern of inter- 

 vening raised lines. Scutellum broader than long, not triangular 

 but with a narrow posterior lobe, distinctly transversely carinate. 

 Elytra not or scarcely sinuate along the outer margin, apices merely 



