SYNOPSIS OF NORTH AMERICAN SYRPHID^. 295 



HEIiOPHIJLiUS. 



TABLE OF SPECIES. 



1. — Face jutting forward into a cone 2 



Face not couically produced forwards 3 



2. — Face obtusely conic hamatus 



Face sharply conical conostomus 



3. — Sixth longitudinal vein distinctly sinuous 4 



Sixth vein uearly straight or only gently curved 7 



4. — Dark colored species 5 



Light colored species; stripes of thorax distinct 6 



5. — Southwestern species mexicaiius 



( glacialis 



Northern species < groenlandicus 



' borealis 



6. — Front of female black pilose; front of male narrow above similis 



Front of female black pilose only near the ocelli ; front of male broad . latifrous 



7. — Antennae reddish yellow 11 



Antennse dark 8 



8. — Third joint of antennas pitchy or more or less reddish 9 



Anteuuoe wholly black 10 



9. — Abdomen with yellow bands obscurus 



Abdomen velvet-like black, each segment with a tringular black shining .spot 



in the middle, and a hoary spot on each side porcus 



10. — Abdomen with light colored bands Novae Scotiae 



Abdomen wholly black modestus 



11. — Abdomen elongate, cylindrical in the male 12 



Abdomen oval ; face yellow 13 



12. — Hind coxse of the male with a stout process below chrysostomus 



Hind coxae of the male not with a stout process distinctus 



13. — Dorsum of thorax with two slender obsolete luteous polliuose stripes . obsoletus 



Dorsum with distinct light colored stripes 14 



f integer 



14. — Abdomen distinctly banded { 



I divisus 



L ? flavifacies 



Third segment, except a small opaque spot in front, and the fourth, shining 



submetallic black bilinearis 



Helophilus bilinearis, n. sp. 



Habitat. — Colorado ! 



S . Length, 9'»'^. Head in profile similar' to that of H. Jcetus, the 

 angle of the cheeks with the occiput a little more obtuse. Face yel- 

 lowish white, clothed with white pollen and pile; cheeks shining black. 

 Antennse reddish yellow; arista luteous. Lower part of the front like 

 the face, on the upper part brownish black with black pile; the pile of 

 the vertex light colored. Thorax opaque black; two median, remote, 

 linear stripes, cinereous, the lateral margins ochraceous cinereous; 

 pile yellowish white. Scutellum obscurely yellow, the narrow base and 

 outer angles black; pile wholly light colored. Abdomen elongate oval, 

 broadest on the second segment; first segment shining, dusted on the 



