220 MEMOIRS ON THE COLEOPTERA 



which however does not extend its range into the Pacific coastal 

 fauna, is distinguishable readily by its small antennae, collaris by 

 the peculiar form of the prothorax, and both this and arizonica 

 differ from inornata in the longer and thicker antennae. The last 

 two species of the table are also peculiar, and especially debilicollis, 

 which has an unusually ventricose form of body and piceous elytra; 

 it also differs considerably in the sexes, as noted above; calif ornica 

 is smaller and narrower than inornata and has the base and apex 

 of the prothorax more nearly equal. Mr. Bates has given rivularis 

 Mots. not Mann, as stated by the author as a synonym of nana, 

 but the descriptions certainly indicate quite a different thing, more 

 notably in coloration, and it is probably a valid species; it occurs 

 at Sitka, Alaska. 



Tachymenis Mots. 



Motschulsky included two quite different genera under his def- 

 inition of Tachymenis, one of which had been described by Kirby 

 under the name Tachyta, a genus of wide northern distribution in 

 both hemispheres. The other generic group, which may be con- 

 sidered typical Tachymenis, since no actual type species was named 

 by the author, includes a few remarkably distinct species, of which 

 flavicauda Say may be regarded as the generic type. The special 

 peculiarity of Tachymenis is the deep even groove along the sides 

 of the pronotum, thinning the integument so that by transmitted 

 light the edge appears testaceous; along the inner edge of the groove 

 posteriorly there is a fine longitudinal carina, accentuating the ab- 

 ruptness of the gutter. Otherwise there is a considerable simili- 

 tude with Tachyta, except that the antennae are still shorter and 

 moniliform, with the second and third joints equal in length but 

 not in thickness, and that the lateral groove of the elytra is more 

 completely and broadly interrupted submedially and more nearly 

 obsolete. The pronotum has the same fine scattered punctures 

 seen in Tachyta. The superciliary punctures bear very long setae 

 and are at an unusually great distance from the inner margin of 

 the eyes, especially the smaller posterior puncture. The Tachyta 

 autumnalis and cucuj aides of Bates, from Mexico and Central 

 America, also belong to this genus, likewise marginicollis Mots., 

 which is really not different horn, flavicauda in all probability; but 



