14 MELANDER AND BRUES. 



to end abruptly before the tip of the first vein. The crotch of the furcation 

 of the Hght vein crossing the anterior cross-vein is darkened by an accumu- 

 lation of pigment and by an increase in the number of hairs. 



Length, 0.85 mm. 



Woods Hole, Massachusetts, August, 1902. 



The nearest relative of this species is C. vampcn?iis Coq. 



It is not unlikely that the species is an halictophile, as it was 

 several times seen upon the nests, thus suggesting its myrme- 

 cophilous relatives. It may also be the cause of the presence of 

 some of the proctotrypida; here listed, as some of them are 

 known to prey on the larvae of various species of the genus. 

 This is the case with Addiopria Ashm., a Diapriid, which is 

 parasitic on a Texan species of Ccratopogon} 



Family Mycetophilid/E. 

 Sciara sp. 

 A Sciara would frequently fly over the nesting-site and alight 

 on the open ground. It is an accidental visitor more at home in 



the nearby grass. 



Family Phorid.e. 



Phora halictorum sp. nov. 



Female. — Length, 1.5-2.25 mm. Head black, subshining, antennae 

 black ; palpi dull yellow, with stiff black bristles below ; proboscis not ex- 

 serted ; front long, flattened, punctured, shining, its bristles reduced in size, 

 and those of the middle row placed high up. Anterior four proclinate 

 bristles small, the remaining ones placed normally. 



Thorax black, subshining, the dorsum finely pubescent, the pleurae 

 lightly pruinose, ten bristles present on the hind edge of the mesonotum, 

 dorsum with one pair of dorsocentral and four marginal scutellar bristles. 



Abdomen black, shining though not brilliant, not bristly, lightly pruinose 

 basally along the sides ; ovipositor short, retractile, piceous. 



Legs piceous, front legs somewhat lighter, front coxae dull yellowish, 

 middle and hind coxae piceous, hind coxa; with the usual ridge on the pos- 

 terior side ; hind femora stoutest, twice as thick as the front ones, middle 

 femora intermediate, all the tibite with short bristles, biserially arranged 

 on their outer side, those of the front tibiae ten to twelve in number and 

 approximated into one line towards the inner forward edge, those of the 

 other tibiae in two separated series, for the middle tibiae four in the outer 

 and six in the inner row, and for the hind tibiae seven in the outer and ten 

 in the inner rows ; front tibiae without terminal spurs, middle tibiae with one 



iSeeWm. H. Ashmead, Biol. Bull., 1902, p. 15. 



