498 PROCEEDINGS OF THE ACADEMY OF [1893. 



and closely punctured ; last dorsal segment not keeled, the eighth 

 ventral segment emarginate ; colored like the 9 . Length 11 mm. 

 Colorado. This species is peculiar in having the eighth ventral 

 plate of the $ emarginate, being the only one of our species of An- 

 cistromma possessing that character. From all the other species it 

 may be distinguished by the robust form, deep-black color and very 

 short antenna; of 9 . 



TACHYTES Panzer. 



Tachytes Panz., Krit. Eev. II. p. 129, 1806. 



Lyrops Illig. Ross., Faun. Etrusc, ed. 2, II, p. 161, 1807. 



Body generally stout, the amount of pubescence with which it is 

 clothed variable, some of the species resembling, in a certain degree, bees; 

 anterior femora of the $ beneath near the base entire or emarginate ; 

 comb on fore tarsi composed of short, thorns or spines; pygidial area 

 large, covered with appressed pubescence, mandibles emarginate be- 

 neath ; their inner margin with one or two teeth ; antenna? stout, 

 shorter than in the two following genera ; eyes converging towards the 

 vertex, the space between them at that point differing in the vari- 

 ous species; fore ocellus round; the hind pair very elongate, placed 

 obliquely and with the upper end forming a hook or flat spiral ; front 

 not raised along the inner orbits as in Notogonia, etc., if anything it 

 is depressed ; sculpture of the thorax not strong; last ventral plate of 

 $ with a rounded, wide emargination ; marginal cell lanceolate, its 

 apex slightly obtuse, the appendiculation small and often indistinct, 

 three submarginal cells, the second of which receives both recurrent 

 nervures ; tibia <ind tarsi of all the legs armed with spines; spines 

 composing comb on fore tarsi generally not longer than the second joint 

 of the said tarsi, and are thorn-like, not at all flexible in appearance; 

 claws not very long ; metanotum shorter than the dorsulum. 



Our species of this genus have been monographed previously ; 5 

 therefore I will simply reproduce the synoptical tables here. In the 

 first place the genus may be -divided into two sections as follows : 



Fore coxse of $ simple, the fore femora of the same sex, beneath at base, 

 entire; thorax of 9 generally densely pubescent. Appearance 

 bee-like Section I. 



Fore coxse of $ with an elongated process, the fore femora of the same 

 sex beneath at the base emarginate; thorax of males not densely 

 pubescent. Appearance not bee-like Section II. 



5 Trans. Amer. Ent. Soc, XIX, p. 234, 1892. 



