AMERICAN DIPTERA. 307 



1. Black species, with black wings (Cuba) funesta. 



More yellowish species 2 . 



2. Body and legs wholly brownish-yellow, without black markings. 



imicolor. 



Body not wholly yellowish 3. 



Thoracic dorsum with three black vittae; bristles of thorax reddish 

 (West Indies; San Domingo, Mex.) lineata. 



3. Thoracic dorsum not so marked; wings brownish with yellowish 



areas 4. 



4. Abdomen unusually slender; eyes closely approximated above, 



ocelli equidistant between the vertex and antennas (Cuba)- 



leptogaster. 

 Abdomen rather stout; ocelli situated higher up than in lepto- 

 gaster (Cuba, Jamaica) indecora. 



Plesiomma unicolor (PL VI, fig. 5.) 



Plesiomma unicolor Loew, Cent., VII, 35, 1866. 

 <$ 9- — Length 19 mm. — Wholly brownish-yellow; posterior margins 

 of the last abdominal segments occasionally slightly darkened; wings 

 blackish, the costal portion of the cells much lighter. 



Entirely brownish-yellow; front, toward the vertex, less narrow 

 than is usual in Plesiomma, and the ocelli much nearer to the vertex 

 than to the antenna?. Face and occiput slightly golden pruinose, the 

 bristles of the mystax more in number, weaker, and arranged in two 

 irregular rows instead of in one, as in most of the species of this genus 

 from North America. Segment 3 of the antennas short, oval, tapering 

 slightly, and with fewer bristles on its upper side than is usual; style 

 bristle-like, nearly one-half as long as the segment. Segments 1 and 

 2 of the antennas, the ocellar tubercle and the occiput, with well de- 

 veloped bristles. The hair of the dorsum longer than usual, of the 

 abdomen short ; on the intermediate segments for the most part black, 

 the rest reddish-brown; the bristles of the entire body brownish- yel- 

 low. Claws black, reddish at base. Wings rather broad, blackish; 

 the center of all the cells, excepting the costal and subcostal, lighter 

 yellowish. 



Type. — M. C. Z. One male and one female specimen. 



Habitat. — N. M.; west Tex. (July 7, Osten Sacken), Cotulla, 

 La Salle Co., Tex. (J. C. Crawford, May 5). 



The female from Cotulla, Texas, leads me to believe that 

 the pale areas of the wing are variable. In this specimen 

 only the second submarginal and the fifth posterior cells have 

 a distinct spot, and there is an indistinct pale band extending 

 from the outer end of the second basal cell to the costa. 



TRANS. AM. ENT. SOC, XXXV. AUGUST, 1909 



