252 DIPTERA OF NORTH AMERICA. [PART IV. 



Mr. Loew under the name of Anisomera succini ; the other was 

 at the time undescribed. Thus while on one side we have four 

 North American species, three of which with long antenna?, and 

 three amber species, two of which with long antennae ; on the 

 other side we see dozens of exotic Eriocerae, and, as far as known, 

 hot a single one with long antenna? among them. A new proof 

 of the remarkable relationship of the North American and the 

 amber fauna ! 



Table for determining the species. 



^ ( Five posterior cells. 1 spinosa 0. S. 



\ Four posterior cells. 2 



2 ( Body light reddish. 3 wilsonii, n. sp. 



( Body dark gray or brown. 3 



o ( Halteres pale. 2 longicornis Walk. 



\ Halteres brown. 4 fuliginosa 0. S. 



Description of the species. 



A. Antennae of the male very long and much longer than those of the 

 female. 

 1. Antennae of the male glabrous on the upper side, and with a series 

 of bristles inserted at regular intervals, on the under side 

 (subgenus ARRHBNICA). 



1. E. spinosa 0. S. % and £. — Fuscescens, thoracis vittis fuscis ; 

 antennis maris corpore duplo longioribus, in pagina inferiori serie 

 spinarum parvarum ; halteres capitulo obscuro ; cellulis posterioribus 

 quinque ; ovipositor feminse valvis superioribus longis, acuminatis. 



Brownish, thorax with brown stripes, antennae of the male more than twice 

 the length of the body, on the under side with a row of spines or bristles ; 

 knob of the halteres dark ; five posterior cells ; ovipositor of the female 

 with elongated, pointed upper valves. Long. corp. % , 0.45 — 0.6 ; 9 > 0.9. 



Syn. Arrhenica spinosa 0. Sacken, Proc. Ac. Nat. Sc. Phil. 1859, p. 244. 



Hale. Head very downy, brownish-gray, tawny on the under 

 side and on the front side of the tubercle ; palpi dark brown, 

 long ; first, second, and fourth joints elongated ; antennae more 

 than twice as long as the body, black, two basal joints tawny ; 

 if bent backwards, the tip of the third joint would reach a little 

 beyond the root of the wings ; the fourth joint is longer than the 

 third, and each of the following joints is longer than the preceding 

 one ; the sixth is as long or longer than all the others together. 

 Thorax brownish-gray, clothed with a soft grayish down ; four 



