218 AMERICAN COLEOPTERA. 



sented near the humerus and towards the apex by the usual marginal setigerous 

 punctures; first dorsal puncture about one-third from base, the second about one- 

 fourth from apex. Body beneath piceous, the head and thorax usually paler. 

 Legs testaceous, the femora sometimes darker. Length .05-. 06 inch ; 1.25-1.5 mm. 



A very singular little species and the smallest in our fauna. The 

 structure of the antennae (PI. VI, fig. 14) is very curious and unlike 

 that seen in any other species, except rufotestaceus, which resembles 

 it in having the second joint longer than the third. The marginal 

 stria of the elytra is obsolete, being represented near the humerus 

 and towards the apex by the usual setigerous punctures, which are 

 to he seen along the margin in most species of Tachys, but the pres- 

 ence of which is often obscured by the depth of the marginal stria. 

 In perfect examples of lasvus the setae proceeding from these punc- 

 tures are seen to be unusually long. 



It occurs throughout the more eastern portions of the country. 

 Specimens have been seen from Canada, Massachusetts, New York, 

 New Jersey, Pennsylvania, North Carolina, Michigan, Iowa, Mis- 

 souri, Arkansas and Louisiana. 



Group VIII. vittiger. 



Form more or less depressed. Head not inserted in the thorax 

 to the eyes; mentum with two deep, forameniforin punctures behind 

 the tooth ; antennae with the second and third joints subequal. 

 Thorax narrowly margined, the margin not translucent. Elytra 

 rounded at tip, with two dorsal punctures, the first on the third 

 stria, when the latter is present, scarcely in front of the middle, the 

 second at or slightly behind the tip of the recurved portion of the 

 sutural stria, but never enclosed within it ; stria? usually feebly 

 marked, impunctate, the sutural only attaining the apex, the latter 

 with the recurved portion parallel to the suture, or nearly so, and 

 hooked at tip; marginal stria broadly interrupted at middle. 



In the males the first two joints of the anterior tarsi are more or 

 less dilated. 



Most nearly allied to the next group, the only character separa- 

 ting them being the different position of the dorsal punctures. A 

 short study of their position in the different species will, I think, 

 convince one that, while in the present group they really belong on 

 the third stria, in the one containing proximus, corruscus, etc., their 

 situation is on the fourth interval. In those species in which the 

 outer striae are feeble or obsolete, the position of the second punc- 



