88 DIPTERA OF NORTH AMERICA. [PART IV. 



Swings with pale brown dots at tlie tip of the auxiliary vein, the origin 

 of the prsefurca, and at both ends of the stigma. 8 tristigma 0. S. 

 Wings entirely immaculate. 9 sociabilis, n. sp. 



Description of the species. 



1. Li. ciiictipes Sat. % and 9 • — Thoracis vittis qtiatuor, femorum 

 annulis duobus fuscis ; halterum capitulo pallido, ad basin fusco ; alse 

 fusco-maculatse et uebulosse ; venula transversalis marginalis juxta 

 apicem venje longitudinalis primae sita,' ocello fusco inclusa. 



Thorax with four brown stripes, femora with two brown bands ; halteres 

 with a pale knob, which is infnscated at the basis ; wings spotted and 

 clouded with brown ; the marginal cross-vein is at the tip of the first 

 longitudinal vein ; a brown, ring-like spot passes over it. Long. corp. 

 0.5—0.6. 



Syn. Limnohia cinctipes Say, Journ. Ac. Nat. Sc. Phil. Ill, 21, 4. — Wiede- 

 mann, Auss. Zw. I, 32, 15. — 0. Sacken, Proc. Ac. Nat. Sc. Phil. 

 1859, p. 214. 



Rostrum and palpi infuscated ; antennae brown, more or less 

 ferruginous at the basis (usually the first three joints) ; front 

 yellowish-cinereous ; vertex'with a large brown spot, divided in 

 two by a yellow line. Thorax yellow with four dark brown 

 stripes ; the intermediate ones separated by a narrow yellow line ; 

 in well-preserved specimens, these stripes are covered with a 

 grayish bloom, except in the middle of the intermediate ones and 

 at the anterior end of the lateral ones, where the color is velvety- 

 black ; humeri yellow, with a small brown dot ; the remaining 

 portions of the thorax are yellow, more or less spotted with 

 brown ; halteres pale, with a brown spot at the basis of the knob ; 

 feet yellow ; femora with two brown bands before the tip, which 

 is yellow ; tarsi infuscated beyond the tip of the first joint. 

 Abdomen ferruginous-yellow, with brown bands across the pos- 

 terior half of the segments ; the bands on the anterior segments 

 interrupted ; venter darker towards the tip in the male ; genitals 

 pale ferruginous. Wings somewhat yellowish, with brown spots 

 and clouds ; four spots along the anterior margin ; the first at the 

 inner end of the basal cells ; the second at the origin of the prae- 



' The structure where the first longitudinal vein is incurved towards the 

 second and the cross-vein is apparently placed between it and the costa, 

 generally occurs in this species and the four following; this cannot prevent 

 us from considering the cross- vein as being at the tip of the first vein. 



