452 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 4^. 



segment is usually entirely black; there is also a black spot on the 

 pleurae between the wing base and another on the posterior surface 

 of the mid coxae; hind femora dilated, apices black, hal teres entirely 

 yellow. 



One specimen, Plummers Island, Maryland, April 26, 1908 (W. L. 

 McAtee), and one. White Mountains, New Hampshire (Morrison), 



APmOCH^TA SUBPICTA, new species. 

 Plate 36, fig. 3. 



This is very closely allied to i^icta Lehm., and also to scalaris Loew. 



Female. — Head, thorax, and abdomen j^ellow, the latter with hind 

 marginal bands dilated laterally on each segment, frontal bristles 

 arranged as in sketch, frons rather narrowed in front, scutellum with 

 four equally strong marginal bristles, mesopleura bare, a black spot 

 on the posterior surface of mid coxae, hind femora as in picta, hind 

 tibial antero-dorsal bristles distinct on basal two-thirds, second abdom- 

 mal segment long, dilated laterally and with a row of about six strong 

 bristles on the lateral surface, costa to well beyond the middle 

 of wing, first section shorter than the second, fringe moderately long 

 and close, fourth vein leaving at fork of tliird with a gentle curve and 

 reaching margin at well in front of the tip of wing, halteres infuscated 

 at tip. 



Length, 2^ mm, A single female from Biscayne Bay, Florida (Mrs. 

 A. T. Slosson). 



This species is very like scalaris Loew, but the hind tibia has only 

 one row of setulae in scalaris, that on the postero-dorsal surface. 



Type.— C&t. No. 14843, U.S.N.M. 



Genus APHIOCH^^TA, Group D. 



TABLE OP SPECIES. 



1. Scutellum with four bristles and mesopleura with a group of numerous bristles 



on the upper posterior angle. (In macrochseta and spinifemorata there are only 

 sometimes one or two small indistinct hairs besides the large bristle present, 



and the anterior scutellar bristles are mere hairs.) 2. 



Scutellum with four or two bristles, but if the mesopleura is bristly as in above 

 species then only two scutellar bristles are present 7. 



2. One very long and strong backwardly directed bristle besides the numerous smaller 



bristles on mesopleura (conf . monochxta and spinifemorata) 3. 



Mesopleural bristles irregular — two or three of those on the posterior margin rather 



larger in size — black species arcuata, p. 460. 



Mesopleural bristles all small, and of nearly equal size; yellow species 6. 



3. Black species; only the hind margins of the abdominal segments narrowly, and 



the legs yellow 4. 



Yellow species; thorax and frons entirely yellow, abdomen more or less yellow. .5. 



4. Frons broader than long, center pair of bristles in first row very little lower on frons 



than outer pair, arista distinctly longer than frons vmrginalis, p. 457, 



