DIPTERA. 135 



Hercostomus Loew. 

 Subgenus Gymno-pternus Loew. 

 H. albiceps Loew. 

 Me.— Mt. Desert, June 10, 1921. 



H. barbatulus Loew. 



N. H.— 11, 12, 15. Vt.— 16. May 26-July 28. 



Mass.— 32. Conn.— 35. May 31-June 25. 



H. chalcochrus Loew. 



Me.— 7, 8. N. H.— 14, 15. Vt.— 21. June 3-July 22. 



H. coxalis Loew. 



N. H.— Hampton, May 3-June 13, 1910 {Shaw). 



H. crassicauda Loew. 



Mass. — Forest Hills; Auburndale, July 1-Aug. 9; Lexington, 

 Aug. 19. Conn. — Danbury, June 15. 



H. debilis Loew. 



N. H. — Hanover, July 6; Hampton, Aug. 7 {Shaw). 



Mass.— New Bedford, July 30 {Hough). 



H. despicatus Loew. 



Me.— 7. N. H.— 11, 14, 15. June 5-July 2-1. 



Mass.—. Conn.— 35. May 27. 



H. difficilis Loew. 



Mass. — Blue Hill, May 30; Brookline, Aug. 23; Auburndale, 

 Aug. 9; Fall River, June 3 {Easton). 



H. exilis Loew. 



N. H.— 15. July 31. 



Mass.— 26, 27, 32. Conn.— 35. July 3-Aug. 30. 



H. fimbriatus Loew. 



Vt.— Brattleboro, July 15, 1908. 



H. flavus Loew. 



Mass.— 25, 27, 29. R. I.— 33. Conn.— 35. July 8-Aug. 25. 



H. frequens Loew. 



Me.— 4, 7, 8. N. H.— 11, 12, 14. Vt.— 16, 18, 20, 22. June 



8-July 22. 

 Mass.— 23, 26, 27, 28, 32. R. I.— 33. June 6-Aug. 23. 



H. humilis Loew. 



Me.— 4, 7. N. H.— 11, 15. May 31-July 17. 



Mass. — 23. Aug. 7. 



H. laevigata Loew. 



Me.— 7. N. H.— 11, 15. Vt.— 22. June 10-July 28. 



Mass.— 23, 26, 27. R. I.— 33. Conn.— 35. May 10-June 23. 



H. mirificus Melander. 



Mass. — {Melander) . 



