FAMILY SYRPHID.i: THE FLOWER FLIES 255 



21). Pleura with sharply limited yellow markings or largely yellow, or the 



abdomen very long and often spatulate 31 



Pleura blackish with at most diffuse yellow markings; rarely a pair 

 of small yellow prescutellar spots; abdomen elliptical or with paral- 

 lel sides 30 



30. Abdomen very long, ihe face and front narrow, the former narrowed 



below (37, 39, 71 ) *Baccha Fabricius 



Abdomen not remarkably long, the face not narrowed below (42). 



fEpistrophe Walker 



31. Abdomen very long, club-shaped, spatulate or with parallel sides; face 



strongly narrowed below; if the abdomen is rather short it is almost 



unicolorous 36 



Abdomen of motlerate length; never spatulate, if rather short and 

 with parallel sides it bears bright yellow markings 32 



32. Large wasp-like species; a pair of small yellow prescutellar spots 



( 83 ) Doros Meigen 



Smaller species, never over 10 mm. in length 33 



33. Mesonotum with a median cinereous or metallic vitta; abdomen usu- 



ally short oval, always very much flattened 34 



Mesonotum without such vitta; abdomen with parallel sides or pointed 

 apically in female 35 



34. Posterior femora strongly arcuate in male, the female abdomen taper- 



ing apically (89, 90) Toxomerus Macquart 



Posterior femora simple; female abdomen obtuse apically. 



JMesogramma Lcew 



35. Male hypopygium globosely enlarged; fifth abdominal segment of the 



female with fasciae which may be broken into spots (72, 88). 



§Sphaerophoria St. Fargeau and Sei-ville 

 Male genitalia small; fifth segment of female with four spots, the 

 median pair longitudinally placed, the outer pair oblique. 



^Allograpta Osten Sacken 



36. Third vein rather deeply looped into the apical cell (Tropical) (11). 



jiSalpingogaster Schiner 

 Third vein not deeply looped into the apical cell 37 



37. Apical crossvein transverse Calostigma Shannon 



Apical crossvein oblique, usually curved (37, 39, 71)..°Baccha Fabricius 



38. Abdomen cylindrical basally (37, 39, 71) °Baccha Fabricius 



Abdomen with parallel sides or elliptical 39 



39. Wings shorter than the abdomen (69, 70, 73, 74) Pyrophaena Schiner 



Wings longer than the abdomen 40 



* Curran, 1930, Amer. Mus. Novit. No. 403. p. 1. 



t Curran, 1925, (Stenosyri.hus). Kans. Univ. Sci. Bull., xv, p. 95. 



J cf. Calostigma Shannon ; Key. Curran, 1930, .\mer. Mus. Novit. No. <05, p. 1. 



§ Curran, 1930, Bull. Amer Mus. Nat. Hist., iNi. p. 61. 



^ Curran, 1932, Amer. Mus. Novit. No. 519. ii. 2. 



11 Curran, 1932, Amer. Mus. Novit. No. 519. p. 5. 



° Curran, 1930, Amer. Mus. Novit. No. 403, p. 1. 



