142 Trans. Acad. Sci. of St. Louis. 



rather a singular circumstance in view of the notable external 

 similarity of this species to aemula; third the rounded 

 sinus of famelica, and, fourth, the pointed sixth segment 

 with very minute notch observable in ambigua, rubida and 

 probably fragilis, these last species differing from the others 

 also in the much more widely diverging gular sutures, less pro- 

 nounced difference between the first and second joints of the 

 hind tarsi and more depressed form, — so that they probably 

 constitute at least a subgenus. The grouping in the table is 

 arbitrary and based solely upon general habitus, in order to 

 facilitate identification. The ambigua group, for example, 

 contains several discordant elements. 



Of the species allied to collaris, as given above — these being 

 likely to prove most troublesome to the identifier, — it may be 

 stated in short that gracilicornis is distinguished by its longer 

 antennae, oregonensis by its larger and broader elytra, follax 

 by the strong pronotal sculpture, vagans by sexual differences 

 in the male and rather more slender form, and, habilis, by 

 its almost completely non-incrassate antennae and very feeble 

 elytral sculpture. There are other forms which appear to be 

 offshoots of the collaris stem, but at present it would serve 

 no useful purpose to describe them. Collaris is an abundant 

 species, widely diffused through the northeastern parts of Ame- 

 rica and is one of the few plicate Lathrobiids thus far known 

 to occur in the New England states. 



Tricolor was stated some years ago by Dr. Horn to be a 

 synonym of ventralis Lee, but I am by no means certain of 

 the correctness of this synonymy, the unique type of ventralis 

 differing considerably in color. Additional comparisons are 

 desirable. The above description is drawn from the original 

 types of tricolor. 



Microlathra n. gen. 



The few species assignable to this genus are readily dis- 

 tinguishable from those of Lathrobiella by the more parallel 

 form, uniformly pale coloration, larger subpyriform head, with 

 very small eyes and a general habitus which strongly recalls 



