March, 1910.] OSBURN : STUDIES ON SVRPHID.'E. 55 



they are obsolete occasionally in the female (the 5. alcidice of Walker and the 

 var. bipunctatus of Girschner). The third vein of the wing is characteristically 

 much curved above the first posterior cell (Fig, 7) and shows no appreciable 

 variation in this respect. In length the species ranges from 8 mm. to 12 mm. 



In Xorth America the species ranges widely over the whole north- 

 ern half of the continent. I have examined specimens from Con- 

 necticut, New Hampshire, New Jersey, District of Columbia, New 

 Mexico, Arizona, Colorado, Idaho, Washington, British Columbia, 

 Alberta and Ontario. 



In Europe the color forms, bipunctatus Girsch. (= alcidice Walk.) 

 and lapponicns Zett., are still variously listed as varieties and species, 

 but a recent letter from Dr. Theodore Becker indicates that he 

 regards all three as the same species, " Syrphus lapponicns Zett. ist 

 keine besondere Art, vielmehr dasselbe Thier wie arcuatus. Diese 

 Art variirt nicht unerheblich : es giebt weibliche Exemplare, bei denen 

 die mondformigen Flecke auf dem hinterleibe fast ganz verschwinden : 

 auch die Schenkel sind an der Basis mehr oder weniger dunkel." 



In America Williston confused arcuatus with the species here 

 described as new, a point he makes clear in a recent letter: " I had no 

 European specimens at the time I wrote. I would call my ' var. 

 lapponicns' arcuatus, of which lapponicus is a varietal synonym. 

 Differences in the color of the femora, unassociated with other dif- 

 ferences, I will not admit can be of specific value, inasmuch as such 

 differences not infrequently appear in other species." 



From my own study of the large series of specimens at my dis- 

 posal I need only remark that Becker and Williston are entirely 

 correct in these expressions of opinion and that henceforth we have 

 only to deal with one variable species. 



Syrphus perplexus, new species. (PI. I, Figs. 4, 5, 6 and 8.) 



Williston, Syn. N. A. Syrph., 68-9 {Syrphus arcuatus var. arcuatus). 

 Banks, Journ. N. Y. Ent. Soc, V, 41 {S. arcuatus'). 

 CoQUiLLETT, Proc. Vyash. Acad. Sci., II, 431 {S. arcuatus). 

 Verrall, Br. Flies, VIII, 381 ( ? 5. arcucinctus). 

 OsBURN, Canad. Ent., XXXVI. 218 {S. arcuatus). 



Male and Female. — Size and general appearance about as in arcuatus. 

 Face yellow with black or brown markings as follows: (i) Two rounded spots 

 one above each antennal fossa and running down nearly or quite to the inser- 

 tion of the antenna (Fig. 4), but showing no tendency toward fusion with the 

 spot of the opposite side. In the female (Fig. 5") the spots may be extended 



