11 



black, silvery-dusted ; metapleura prominent ; coxae concolorous except 

 extreme tip, fore coxre bronze-dusted in front. Legs black, except the 

 following : Tips of femora below, basal two-thirds of middle and hind 

 tibial, and front metatarsi, which are dark yellowish. The fore legs are 

 ornaiiiented as follows : Tibiae thickened, dusted with yellow on anterior 

 surface, and with longitudinal rows of short black bristles ; tarsi com- 

 pressed, first joint a little shorter than the rest together, pulvilli large. 

 Wings hyaline ; anal angle much fuller than in angustipennis ; fourth vein 

 turned forward toward third, ending considerably before the tip of the 

 wing ; posterior cross-vein distant its length from the apex of the fifth vem, 

 bowed inward and surrounded by a very faint cloud. Tegular cilia black. 



77^;;;^/^, —Length 5.5 mm., of wing 5 mm. Differs as follows from 

 the male : Face ochraceous. Infra-ocular cilia a little stronger. Vertex, 

 thorax, and abdomen a more brassy, brighter green. Red at tip of femora 

 more spread, and at base of middle and posterior tibi;e more restricted; 

 fore tibia; yellow, with ordinary bristles ; fore tarsi not compressed, first 

 joint equal to next three. Wings with faint yellowish tinge, cross-vein 

 more oblique. 



One male from Clementon, N. J., May 10, 1896, and one female 

 from Delaware Water Gap, N. J., July 8. Both specimens were received 

 from Mr. C. W. Johnson. 



The following combination of characters briefly distinguishes this 

 species from all the known species of Tachytredms : 



Male artista without an enlargement; fourth vein curved forward, 

 ending near third and distant from tip ; cilia of inferior orbit pale ; wings 

 unspoued; antenna; largely red ; fore femora plain, more or less yellow- 

 tipped. 



In 1878 Mik* established the genus Macellocerns, basing it upon 

 Tachytrechus mcechus, Loew. From Tachytrechus this genus differed 

 thus : " Zweites Fuehlerglied rudimentaer, das dritte klein, mit ausseror- 

 denilich verlaengerter, dorsaier Borste, welche am Ende schaufelfoermig 

 erweitert ist. Der letzte Abschnitt der vierten Laengsader convergirt stark 

 gegen die dritte, so dass die Muendungen dieser beiden Adern nahe einan- 

 der stehen." The addition of protervus leaves Macellocerus based upon 

 a single male character. Concerning the inadvisability of erecting a 



genus upon mcechus, Dr. Loew had alread y written. f 



*Zur Kenntnis der Dolichopodiden, Dipterologische Untersuch ungen, p. 5. 

 tMorographs of N. Am. DolichopodidK, p. 112. 



