GERON. USIA. 281 



proboscis black ; antennae black, relative length of joints as in 

 argent ifrons, tips of first two joints narrowly pale, with greyish 

 hairs ; occiput black, with long yellow hairs above and greyish 

 ones below ; hind margin of eyes with small white scales. Thorax 

 velvet-black, dorsum covered with bright yellowish hairs, which 

 are greyish on the grey shoulders ; underside ash-grey, with long 

 grey hairs and some grey scales ; scutellum black, yellow-haired. 

 Abdomen black, with minute bright yellow fine scales and hairs ; 

 hind margins of segments with long deflexed grey hairs ; whole 

 dorsum with long thin greyish pubescence, which is denser at the 

 sides ; venter wholly covered with small silvery-white scales and 

 long grey hairs. Legs with coxae and fore femora black, former 

 with grey hairs ; posterior femora and all tibiae pale tawny ; tarsi 

 black, middle metatarsi more or less pale at base ; legs almost 



Fig. 18. Geron albescens, Brun., wing. 



bare except for a few short hairs below femora and the usual 

 minute tibial bristles. Wings quite clear, veins pale yellowish on 

 basal half; halteres yellowish, knobs bright pale yellow. 



Length, 5-8 mm. 



Redescribed from the original type from Balugaon, Puri Distr., 

 Orissa, 14. xii. 1908 (Gaunter), and a second J from Tambi, 

 Satara Distr. ; Bombay, 2100 ft., 22-26. iv. 1912 (Gravely), both 

 in the Indian Museum. 



^.-The only definite character by which this species differs from 

 argentifrons seems to be the pale posterior femora in the J and 

 the larger size. 



Genus USIA, Latr. 



r/Vi, Latreille, Hist. Nat. Crust. Ins. xiv, p. 300 (1804). 

 Volucella, Fabricius .(nee Geoff.), Ent. Syst. iv, p. 412 (1794); id., 

 Syst. Antl. p. 114 (1805) ; Meigen, Klass. i, p. 194 (1804). 



GENOTYPE, Volucella florea, F. (Europe) ; by Rondani's desig- 

 nation. 



Rather small bare or nearly bare flies, sometimes of metallic 

 ground-colour, sometimes with yellow and black markings. Head 

 hemispherical, small, set rather low on the thorax; epistome 

 short, proboscis prominent, at the base membranous, apical part 

 horny with extremely narrow labella ; palpi short, united to the 

 basal part of the membranous portion, which is entirely with- 

 drawable within the mouth-border. Antennas short, porrecl, 

 hardly longer than head, approximate at base ; the first two joints 

 subequal ; 3rd elongate, spindle-shaped above, blunt, with spines 



