430 COQUILLETT 



male, his simple middle tibice and the absence of bristly hairs on all 

 the tibiae. 



Platychirus aeratus sp. nov. 



Male : Differs from the above description of tenebrosus only as fol- 

 lows : Frontal triangle and face, except the tubercle, thinly grayish 

 pruinose, thorax and scutellum bronze black, the hairs yellow ; abdo- 

 men marked with a pair of gray pruinose, bronze colored, subellipti- 

 cal spots at the anterior outer angles of the third and fourth segments ; 

 front femora, except the apices, black, their tibicE gradually and mod- 

 erately dilated toward the apices, their tarsi only moderately dilated and 

 of n^rly an equal width, the first joint almost as wide as broadest part 

 of the tibijE, about twice as long as wide ; middle tarsi brownish yel- 

 low, the bases broadly yellow. 



Female: Resembles the male with these exceptions: Lower half 

 of front thinly gray pruinose, most dense along the eyes, abdomen 

 polished and destitute of spots; front femora sometimes yellow except 

 on the outer side, their tibiae only slightly dilated, middle femora, tibiae, 

 and tarsi sometimes yellow except on posterior sides of femora, wings 

 pure hyaline. Length 5 to 7 mm. 



Two males and two females, collected June 12. 



Habitat. — Muir Inlet, Alaska. 



Type. — Cat. no. 5239, U. S. National Museum. 



A very slender species, closely related to albimanus., but in the lat- 

 ter the head is much longer at the anterior oral margin than at base 

 of antennse, the front femora of the male bear several hooked bristles 

 on the posterior side before the middle, his front and middle tibiae 

 have several rather long bristly hairs on the outer side, and the ab- 

 domen of the female is spotted "^learly the same as in the male. 



Platychirus albimanus (Fabricius). 



Syrp/ius ci/bimanus Fabricius, Species Insectorum, 11, p. 434, 1781. 

 Platychirus albimanus Schiner, Fauna Austr., Diptera, I, p. 294, 1862. 



Sitka, June 16; Popof Island, Alaska, July 14 and 16: Three 



males and one female. A European species, not heretofore reported 



from this Continent. 



Leucozona leucorum (Linne). 



Musca leucorum Linne, Fauna Suecica, p. 1803, 1761. 



Leucozona leucorum Schiner, Fauna Austriaca, Diptera, i, p. 299, 1862. — 

 WiLLlSTON. Synopsis N Am. Syrphidie, p. 62, 1886. 



Popof Island, July 13; Saldovia, July 21; Juneau, Alaska, July 



