246 DIPTERA OF NORTH AMERICA. [PART II. 



II. Tegulse with pale cilia. 



A. Antennae entirely black. 



15. scintillans Lw. 



B. The two first joints of the antennae pale. 



a. Fore femora in both sexes, or at least in the % , without yellow 



thorn-like bristles upon the under side. 



1. Abdomen at the basis not yellow. 



16. pallens Wied. 



2. Abdomen at the basis yellow, not metallic. 



a. Tarsi for the most part black. 



17. variegatus Lw. 



b. Tarsi towards the end but little infuscated. 



a. All the coxae entirely yellow. 



18. bicolor Lw. 



0. Middle coxae gray with yellow tip. 



19. psittacinus Lw. 



b. Fore femora in both sexes with yellow thorn-like bristles upon 



the under side. 



1. All the coxae entirely yellow. 



20. tener Lw. 



2. Middle and hind coxae blackish. 



21. filipes Lw. 



Description of the Species. 



I. Tegulse ciliated with black. 



A. Wings with a black picture. 



a. Wings black, only the tip and the hind margin hyaline. 



1. P. dimidiatllS Loew. % . — Nitidissimus, capite thoraceque vio- 

 laceis, abdomine viridi ; pedes simplices, graciles, femoribus nigris, tibiis 

 flavis, tarsis fuscis ; alae ex fusco nigrae, triente apicali et margine pos- 

 tico hyalinis. 



Very shining ; head and thorax purplish-blue, abdomen green ; feet plain 

 and slender with black femora, yellow tibiae and brown tarsi ; wings 

 brownish-black, the last third and the hind margin hyaline. Long, 

 corp. 0.17. Long. al. 0.19. 



Syn. Psilopus dimidiatus Loew, Berl. Ent. Zeitschr. VI, 216, 70. 



