Syuphus of Meigen is so large a group that it would be very 

 desirable to divide it if good generic characters could be found; 

 but I am not prepared to say that Scseva differs from Syrphus 

 in structure, although the species may be distinguished by 

 their transparent and immaculate wings, and their ornamented 

 and very depressed abdomens ; the clypeus also seems to be 

 less tuberculated and projecting than in the Syrphi. 



Restricted as the Genus now is, it contains 28 species in- 

 habiting this country, for a list of which I must refer to the 

 Guide. 



The rare Insect figured may be only a singular variety of 

 S. selenitica wanting the yellow spots on the abdomen : it was 

 taken, I think, in the neighbourhood of London. 



Two of the species {S. Pyrastri Linn., and S. selenitica 

 Meig., which is probablyonly a variety of the former,) sometimes 

 appear in myriads on the sea-coast, all flying in one direction, 

 and not even avoiding objects that lie in their course. A 

 Lady informed me that on Thursday the 30th of July 1818, 

 which was a very hot day, they quite covered the fishermen's 

 boats at sea off Broadstairs : the next day was cloudy with 

 several slight showers, when scarcely any were to be seen. 

 Saturday and Sunday were warm days, when a few were ob- 

 served flying about, and on the Monday they had entirely 

 disappeared. They were equally abundant at Ramsgate and 

 at the Nore. The larvae of these flies feed on Aphides, and are, 

 I believe, of great value in clearing the Hop-grounds of that 

 destructive insect: they are so admirably described by Rusticus 

 in the Entomological Magazine that I cannot refrain from 

 giving his account of them. " Besides the Lady-bird and its 

 grub, there are two other terrible enemies to the poor Aphis; 

 one of which is a green ungainly-looking grub, without legs, 

 which lies flat on the surface of the leaf, and stretches out its 

 neck, just like a leech, till it touches one of them; directly he 

 feels one he seizes it in his teeth, and holds it up, wriggling in 

 the air till he has sucked all the goodness out of it, and left it 

 a mere empty skin." Equally interesting accounts will be 

 found in the 1st vol. of Kirby and Spence's Introduction to 

 Entomology, p. 257. and vol. 2. p. 275. I may add that I 

 found the larvae of S. Pyrastri in some abundance in the middle 

 of July 1829, on the Sea-cabbages (pi. 352.) growing under 

 Dover Cliffs. The flies appear from June to the middle of 

 October, hovering over flowers in gardens and hedges. I have 

 observed them on paling in the morning at the end of Sep- 

 tember, and the beginning of October I have found the females 

 resting, and the males at the same time on the wing, but much 

 less numerous than the other sex. 



The Plant is Fragaria sterilis (Barren Strawberry). 



