88 DIPTERA OF NORTH AMERICA. [PART IV. 



/ Wings with, pale brown dots at the tip of the auxiliary vein, the origin 



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



' Wings entirely immaculate. 9 sociabilis, n. sp. 



9 



Description of the species. 



1. L.. cinctipes Say. % and J . — Thoracis vittis quatuor, femorum 

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

 fusco-maculatse et nebulosse ; venula transversalis marginalis juxta 

 apicem vense longitudinalis prjmse sita, 1 ocello fusco inclusa. 



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

 with, a pale knob, which is infuscated 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. Limnobia 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 ; antennse 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 prse- 



1 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 x>revent 

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



