54 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.51. 



clothed with brassy yellow pile; front broad, inner orbits parallel: 

 distance from ocelli to antennae much less than least distance between 

 the eyes; ocelli approximate; antennae black, the first joint slightly 

 shorter than the two following together, second joint about (or 

 slightly over) half as long as third; third joint considerably shorter 

 than first, pointed at tip; thorax black, with obscure purplish and 

 green tints, the dorsum clothed with fox-red pile; scutellum short, 

 rounded, transverse but projecting, not emarginate, its pile longer and 

 brighter red than that on mesothorax ; abdomen short, broad, black, 

 pile long on margins of segments, reddish yellow, abundant on first 

 and second segments, especially at sides, and on apical margin of 

 third ; legs black, femora and tibiae clothed 

 with reddish yellow pile; hind basitarsi 

 not as long as remaining joints together, the 

 whole hind tarsi thick, but the basitarsi not 

 especially so ; wings pale gray, veins black- 

 ish; vein forming outer side of discal cell 

 strongly curved, finally directed upward 

 FIG. i.-MicRODON C0L0EADENSI3. foi-jninff an obtusc angle on outer side with 



Wing OF MALE. ^ ^ . n t 



vein boundmg first posterior cell; distance 

 on upper side of first posterior cell from base to stump less than from 

 stump to end ; halteres cream color. 



Female. — A little larger, width of abdomen over 7 mm.; differs 

 from male in having the pile on head and thorax whitish yellow ; pile 

 on abdomen forming a broad pale yellowish shining band on hind 

 margin of first segment, but black on 

 sides of that segment anteriorly; on 

 the other segments thin and black, 

 with a few pale hairs on lateral hind 

 margins of third segment. 



Pupa. — Of the usual form and red- 

 dish color; length 10.5-12,5 mm., 



• ■Ki.-K i-r K I'li-r-r M FiG. 2.— MiCRODON COLOEADENSIS. EGG. 



width 7,5 mm,, height 5,5 mm, ; easily 



distinguished from those of M. tristis and varieties by the absence 

 of raised lines or other distinct sculpture ; the surface is uneven, with 

 small and obscure pustuliform elevations, arranged more or loss in 

 longitudinal rows. The posterior tubercle is relatively long and 

 narrow, its length conspicuously greater than its apical breadth, 

 whereas in tristis^ variety, it is broad and short, its length much less 

 than the apical breadth. 



Egg. — Long-oval, white, about 1.75 mm. long, the surface regularly 

 and densely beset with protuberances, giving a coarsely granular ap- 

 pearance under a lens. 



Type.— C^i. No. 19727, U. S. Nat. Mus. 



