.iNSECUTOR INSCITI^ MENSTRUUS 133 



FURTHER NOTES ON SYRPHID^ 



By FREDERICK KNAB 



Baccha fuscipennis Say. 



This species was discussed by the writer in the last issue of 

 this journal, page 92. In this connection should have been con- 

 sidered Loew's Baccha lugens, which, it seems, systematists have 

 found much trouble in differentiating from fuscipennis. The 

 reason for this difficulty lies in the fact that lugens was 

 described from an immature specimen of fuscipennis. A num- 

 ber of such specimens before me answer perfectly to the 

 description of Loew. The clear spots in the centers of the 

 wing-cells appear to have been considered diagnostic for 

 lugens, and this, precisely, is what is to be found in immature 

 specimens of any species with infuscated wings. Freshly 

 emerged specimens first show signs of pigmentation in a pale 

 gray tint along the veins, this tint gradually becoming darker 

 and spreading into the cells. When the coloring process is 

 well advanced but still incomplete, we have the condition 

 described by Loew for lugens — a dark wing with clear spots 

 in the centers of the cells; with time these clear spots, too, 

 assume the general dark tint. 



This coloring process is beautifully illustrated in a series of 

 reared specimens of Ocyptamus latiusculus Loew from Porto 

 Rico in the national collection. This series contains all inter- 

 grades, from the very recent specimens with narrow streaks 

 along the veins to the mature ones with uniformly tinted wings. 



To the synonymy of Baccha cylindrica, page 91, should be 

 added Syrphus peas Walker, 1849, List Dipt. Brit. Mus., pt. 3, 

 p. 590. Although no locality is given, the identity is made 

 certain by the indication of the contrastingly black and yellow 

 femora. 

 Ocyptamus simplex (Loew). 



Syrphus simplex Loew, Wien. Ent. Monatschr., v. 5, 1861, p. 40. 



Syrphus simplex Loew, Centuries, vi, 1865, no. 43. 



Syrphus simplex Williston, Synopsis N. A. Syrph., 1886, p. 87. 



Originally described from a Cuban specimen and later re- 

 ported by Williston from Santo Domingo. The latter specimen 



