128 Bulletin of the Brooklyn Entomological Society Vol. XVI 



4. Face in profile evenly hollowed; arista shorter than anten- 



nae; upper edge of third antennal joint with groove-liks 

 impressions, apparently formed to receive the arista. 



Merodon. 

 Head of Eristalis type; arista distinctly longer than anten- 

 nae, third antennal joint without groove-like impression. 



Mallota. 



5. No stigmatical crossvein ; epaulet at base of costa broad 



and clothed with mostly yellowish hairs ; squamae broad, 

 bordered by dense, straight cilia ; abdomen broad with 

 yellow markings. (H. similis group : H. similis, lati- 

 frons, dychei, horealis, pendula of Eu. ; and probably gla- 



cialis and groenlandicus) Helophilus. 



Stigmatical crossvein present 6. 



6. Large robust species, about 17 mm.; hind tibiae of both sexes 



arcuate ; sides of second tergite of female folding down- 

 wards, covering the membranous tissue at sides of second 

 stemite; abdomen of male narrowing posteriorly {P. 



curvipes) Polydontomyia. 



Smaller species, either 11 mm. or less and broad, or 12-14 

 mm. and slender ; hind tibiae straight or gently arcuate ... 7. 



7. Ocelli widely separated in both sexes ; mesonotum with very 



indistinct stripes ; pleurae and all femora shining black ; 

 squamal cilia unbranched; broad species. (A. mexicanus 



and willingii) Asemosyrphus. 



Ocelli not unusually far apart 8. 



8. Slender species; squamal cilia branched. (H. chrysostomus 



and distinctus) . Helophilus. 



The remainder: hamatus, conostoma, porcus, fnodestus, in- 

 teger, IcBtus, hilinearis, lunulatus, etc., are of several types 

 more easily recognized by habitus than otherwise. 



(Continued in February number.) 



Wanted — Brief notes to fill such spaces as these. — Ed. 



