160 BULLETIN 31, UNITED STATES NATIONAL MUSEUM. 



14. — Frout of feiuale narrow. Dcei) bluish black ; scutelhim but very little lighter; 

 second segment of abdomen with inconspicuous side spots; third and fourth 



segments with a narrow anterior velvety fascia saxorum 



Front of female broad; dorsum of thorax not shining steel-blue .... 15 

 15. — Lighter markings of abdomen usually quite distinct ; third and fourth segments 



with a small, elongate, opaque black spot in frpnt hirtus 



Light markings obsolete, third and fourth segments without opaque anterior 

 . S obscuriis 



"l^°* iinoruatus 



16. — Third segment of abdomen with an anterior spot and a posterior, opaque cro.ss- 

 band ; the ojjaque of second segment with a small triangular shining si>ot 

 behind; fourth segment with an oval spot in front .... dimidiatus 

 Third segment with one or two small opaque spots only, without posterior cross- 

 band ; or wholly shining 17 



17. — Wings conspicuously dark colored on the outer i^art in front ; hind femora 



thickened hortorum 



Wingshyaline, femora not thickened . 18 



18. — Second segment of abdomen with yellow lateral triangles and a posterior, inter- 

 rupted or subinterrupted velvety cross-band ; posterior margin of segments 

 2-4 yellowish white with a fringe of pale golden pile .... latifrons 

 Second segment, except the obsolete or metallic side spots, which extend the 

 whole length of the segment, velvety black; third usually with a velvety 

 triangle in frout, the fourth with a similar, but very small one ; the yel- 

 lowish white hind borders fringed less con.spicuously with light colored 



pile Brousi 



19. — Second, third, and fourth segments of abdomen broadly reddish yellow on the 

 sides, leaving a narrow black stripe, which is wholly opaque on the second 

 segment, and in front, at least, on the third segment ; eyes narrowly sepa- 

 rated ((J) montanus 



Second, third, and fourth segments not broadly yellow on the sides . . . 20 

 20. — Third segment with two opaque circular spots near the middle of the segment, 



pilosus 



Third segment with a posterior opaque cross-band 21 



21. — Posterior opaque cross-band of third segment narrow ; fourth segment usually 



with a small ojiaquo spot in frout . occidentalis 



Posterior cross-band broad ; fourth segment wholly shining ; more thickly pilose 

 species Bastardi 



For other species, see descriptions. 



Eristalis tenax. (Plate VII, tigs. 7, 7a, 76, 7c.) 



Musca tenax Linn6, Fauna Suecica, 1799 (1761). 



Miisca porcina Degeer, Ins., vi, 45, 1. 



Conojjs vulgarin Scopoli, Eutom. Cam., 354, 960. 



Conops f 1186118 Scopoli, 1. c, 355, 961. 



ElopHlus tenax Latreille, Gen. Crust., iv, 324. 



Syrphua tenax Fabricius, Spec. Insect., ii, 425; id. Entom. Syst., iv, 288, 36; 



Fallen, Syrph., 26, 17; Zetterstedt, Dipt. Scand., ii, 661,7; id. ibid., viii, 



3113, 7. 

 Eriatalis tenax Fabricius, Syst. Antl., 238, 24; Meigen, Syst. Beschr. iii, 385, 4; 



Macquart, Hist. Nat. Dipt., 1, 504, 21 ; Schiner, Fauna Austr., i, 334; Burgess, 



Psyche. 



Habitat. — Europe, Asia, Africa (Auct.), North America, Japan ! 

 ^ , 9 . Length, 12 to 14'"'°. Eyes with dark pile, more abundant near 

 the middle, in the form of an elongated vertical stripe or ellipse, the 



