14 



This species probably does not occur in fields, but in mountainous 

 districts it may be not uncommon. 



% Silvias dorsalis, Coquillett. (PI. I, fig. 2.) 



fHime-Abti.) 



Proc. U. S. N. Mus., XXI, p. 309, 1898. 



Ricardo, Ann. Mag. Nat. Hist., (7), VIII, p. 292, 1901. 



A middle-sized yellowish fly, with a large brown or black frontal 

 callus. 



Female. Frons about one fourth the width of the head, 

 longer than width, somewhat elevated, quadrate, almost parallel- 

 sided and diverging just above the antennae, greyish yellow, but mainly 

 covered by a large polished brownish black or black callus, which is 

 oblong, hardly reaching from the middle ocellus to above the antennae, 

 and is distinctly elevated ; a distinct transverse sulcus just below the 

 frontal callus, the sulcus slightly angulated downwards at the middle, 

 orange yellow on the spase between the antennae and frotal callus but 

 at the middle part somewhat brownish in a darker specimen. Pubes- 

 cence blackish, very sparse, entirely absent at the lateral parts of the 

 two-thirds below. Vertex dull yellow, moderately convex at the middle, 

 with three rather large brown or dark brown ocelli in a triangle, with 

 a few blackish hairs behind the ocelligerous elevation. Face slightly 

 arched, pale orange yellow, bearing two rather large polished brownish 

 or blackish spots, which are occupying the deep pits on the sides of 

 the middle part of the face, and with two fine but distinct longitudinal 

 sulca which are reaching from the deep facial pits to the base of the 

 antennal prominence ; two oblique rather broad polished bands from 

 the facial pits to the oral margin, at where they are hardly united each 

 other ; pubescence blackish, rather sparse, entirely absent on the middle 

 part of the face and around the polished spots, and longest and stout 

 on the oral part, at where a few transverse wrinckles are conspicuous. 

 Jowls very short, clothed with rather abundant blackish hairs which are 



