54 Journal New York Entomological Society. [Voi. xviii, 



D. W. Coquillett, N. Banks, E. L. Dickerson, R. V. Harvey and 

 B. G. Elliott among the American entomologists, and Dr. Theodore 

 Becker, Liegnitz, Germany, Professor Mario Bezzi, Turin, Italy, and 

 Mr. E. E. Austen, of the British Museum. 



The following redescription of Syrphus arcnatns is drawn from 

 about fifty specimens, both American and European, covering a wide 

 range in distribution, and dealing only with essential diagnostic 

 characters. 



Syrphus arcuatus Fallen. (PI. I, Figs, i, 2, 3 and 7.) 



Fallen, Syrphici, 42 (Sccpva arcuata). 



Meigen, Syst. Beschr., Ill, 302 (Syrphus arcuatus). 



Zetterstedt, Ins. Lapp., 598 (Scava lapponica). 



Walker, List, etc.. Ill, 579-80 (Syrphus agnon, alcidice and arciicinctus). 



Schiner, Verb. Zool.-Bot. Ges., VII, 344 (Syrphus arcuatus and lapponicus). 



O. Sacken, Proc. Host. Soc. Nat. Hist., XVIII, 149 ; West. Dipt., 326 (S. 



lapponicus). 

 Girschner, Wien. ent. Zeit., Ill, 187 (var. bipunctatus). 

 RoNDANi. Att. Soc. Ital. Milano, VIII, 135 (Syrphus lapponus). 

 WiLLiSTON, Syn. N. A. Syrph., 68-9 (the var. lapponicus only). 

 Verrall, Br. Flies, Syrphidae, 380 (arcuatus and var. ? lapponicus) ; idem, 



Catalog, 61-2 (as two species). 

 OsBURN, Canad. Ent., XXXVI, 218 (the var. lapponicus only). 



Male and Female. — Face yellow, a biarcuate black band (PI. I, Fig. i) 

 transversely placed on the ridge above the antennal fossae, not reaching down- 

 ward on the fossa? except in rare cases. This band is usually narrow and is 

 sometimes brownish, but it is never dissolved into spots. In the female 

 (Fig. 2) it is usually broader than in the male and may or may not be con- 

 nected with the black of the vertex at the middle by a narrow band. The- 

 cheeks are black and usually connected along the oral margin with the black 

 facial stripe (Fig. 3) ; there is considerable variation in the oral coloration, it 

 may be merely brownish, as the facial stripe occasionally is, and in a few 

 cases the cheeks and facial stripe are disconnected, this seems especially true 

 of the European specimens in my possession. The eyes of a few of the males 

 show some enlargement of the upper facets, with a distinct line of separation 

 as in Catabomba, but usually they intergrade insensibly. The few males from 

 Europe in my collection do not have the enlarged facets separated. The pile 

 of the sides of the throax is usually yellowish like that of the disk, but it 

 shows some variation in depth of color, depending apparently on age, tenerals 

 being somewhat lighter. Legs dark at the base, exhibiting considerable varia- 

 tion in the extent of the marking, which may range all the way from the 

 extreme base to one half or more of the femora. (This latter condition is the 

 lapponicus Zett., in which nearly all of the North American specimens fall.) 

 The abdominal arcuate spots also show much variation in curvature and extent : 



