ALDRICH AND DARLINGTON. 69 



raesopleura, the size of the second fronto-orbital, the pubesceoce of 

 the scutelluni, etc. The constancy of some of the most minute of 

 these characters is interesting. 



Our work is based primarily on the collections of the senior 

 author, in which the types, unless otherwise mentioned, . will be 

 retained. Important additional material was received from Prof. 

 A. L. Melander, Pullman, Wash. ; C. T. Brues, Milwaukee, Wis. ; 

 C. W. Johnson, Boston, Mass. ; Erich Daecke, Philadelphia, Pa. ; 

 and the United States National Museum. A few specimens came 

 from Prof R. A. Cooley, Bozeman, Montana; E. S. Tucker, Law- 

 rence, Kansas ; and C. F. Baker, now of Para, Brazil, but in Cali- 

 fornia at the time of making these collections. 



We have cited literature only when the same is not found in 

 the 1905 Catalogue, except when changes of synonymy, etc., are 

 involved. The rest may be found in the Catalogue. 



A side view of the thorax oi' Anorosto77ia macxUata, somewhat dia- 

 grammatic, to show the sclerites and bristles, the origin of the latter 

 represented by small circles, is given on Plate III. 



TABLE OF GENERA. 



1. Thorax with long pile, dorsoceutrals but little differentiated. 



l>eria helTOla male. 

 Thorax with shorter pile, dorsoceutrals well developed 2. 



2. One dorsocentral Porseiius new gen. 



Two dorsoceutrals AchSBtomus Coq. 



Three dorsocentrals Tephrochlamys Loew. 



Four dorsocentrals 3. 



Five dorsocentrals 4. 



3. Middle tibise with spines on the outer side near the middle. 



CEcothea Haliday. 

 Eyes very small, with vertical diameter less than the cheeks (PI. IV, fig. 3). 



Eccoptomera Loew. 

 Face very receding, convex in profile, without distinct oral margin (PI. IV, 



fig. 4) Anorostoma Loew. 



Without the above characters Lieria Loew. 



4. Humeral bristle absent H<'loniyza Fall. 



Humeral bristle present 5. 



.5. No bristle on mesopleura ... Allophyla Loew. 



A bristle on posterior part of mesopleura Siligo new gen. 



PORSENHS Darlington, n. gen. 

 Humeral and propleural bristles absent; only one dorsocentral 

 (the hindmost) ; only one supra-alar (the foremost) ; presutural 1 ; 

 notopleural 2 ; scutellar a very large apical pair and a small lateral 



TKANS. AM. ENT. SOC. XXXIV. MABCH, 1908. 



^yy 



