30 COSTA RICAN DIPTERA 



Aphiochaeta pruinosa new species 



Male.— Black shining. Frons covered with grayish poUinosity, palpi 

 yellow. Mesonotum slightly poUinose; ])lein-a shining, the upper third 

 poUinose. Abdomen colored as mesonotum; anal protuberance yellow. 

 Legs black-brown, fore pair and bases of posterior pairs of tibiae yellowisli. 

 Halteres yellow. Wings clear, veins black-brown. 



Frons with distinct central furrow, as in litoralis, lower post-antennal 

 bristles minute, upper pair and all frontal bristles strong; central bristles in 

 first row distinctly lower on frons than outer pair; third antennal joint above 

 the average size; arista pubescent, slightly lower than frons; palpi normal 

 in size and bristling. Scutellum with 4 bristles, the basal pair the weaker; 

 mesopleura bare. Abdomen rather broad; second segment with 4-5 lateral 

 bristles; anal protuberance large, the apical hairs present. Legs stout; 

 fore tarsi slightly broadened throughout their entire length; hind femora 

 bare vent rally at apex; hind tibial setulae of moderate strength. Costa 

 to slightly short of wing middle; first division distinctly, but not greatly 

 larger than 2-|-3; the angle at junction of vein 1 with costa obtuse; fork of 

 third forming an obtuse angle; fourth vein gently arcuate; costal fringe 

 close and of moderate length, each bristle being about 3 times as long as 

 costal diameter. Length, 2 mm. 



Holotype. — Near Cartago, December 15, 1909, south slope of 

 Irazii, over mud. Type No. 6042. 



Aphiochaeta sylvicola new species 



Female.— Shining brown-black. Frons slightly poUinose; antennae 

 brown; palpi yellow. Alesonotum slightly poUinose; pleura glossy, the 

 upper portions poUinose. Abdomen opaque black. Legs brown, fore pair, 

 including coxae, clear yellow, mid and hind pairs with tibiae yellowish. 

 Wings clear, veins brown. Halteres black-brown. 



Frons slightly broader than long; central furrow distinct; lower pair of 

 post-antennal bristles very minute, upper pair strong; central pair of bris- 

 tles in first row almost in transverse line with upper post-antennals and 

 slightly lower than outer pair in same row, the latter more widely separated 

 from the central pair than that pair are from the post-antennals; surface 

 hairs on frons very short and close; antennae normal in size and shape; 

 arista pubescent, distinctly longer than frons; palpi as large as third anten- 

 nal joint, moderately bristly. Mesonotum with short dark surface hairs; 

 mesopleura bare; scutellum with 2 bristles and 2 weak hairs. Abdomen 

 ovate; second segment with 3-4 hair-like bristles on lateral margins. Fore 

 tarsi slightly thickened; hind femora with short hairs on the ventral sur- 

 face; hind tibial setulae 8-9 in number, increasing in size to beyond middle 

 and then slightly decreasing, the longest part not equal to the tibial diam- 

 eter. Wing with costa to distinctly beyond middle, first and second costa! 

 divisions subequal, angle of fork of third vein acute; fourth vein leaving 

 with a gentle curve at slightly beyond fork and ending, reciu-ved, at well in 



