54 H. C. EFFLATOUN. 



larvae and examined the developmental stages of many European 

 species of Syrphus in Denmark amongst which he mentions 5. 

 corollas, the larva? of which he found among Aphids on Prunus on 

 June 3rd and which developed into adults on June 22nd; S. bal- 

 teatus, the larvae- of which he found among Aphids on Sambucus 

 and on Brassica, and pupa? of the same species on Rosa, Rheum, 

 Typha, and Phragmites. He describes the larva as being "always 

 more or less leech-like ; it is somewhat flattened with a flat ventral 

 surface, the dorsal surface more or less slightly arched; the body 

 is attenuated or pointed towards he head-end, broad behind, 

 sometimes a little rounded; it is more or less strongly transversely 

 corrugated so that the single segments are not easily made out. Be- 

 low there are seven more or less distinct, transverse swellings, 

 which may be more or less distinctly devided into proleg-like 

 warts, and have small spines. The larvae may otherwise be some- 

 what different; some are almost smooth above, the dermis only 

 finely shagreened, and there are short, soft bristles on some of the 

 corrugations and at the sides; in others the shagreened structure is 

 developed into a clothing of five, short and dense spines, and there 

 are the same soft bristles; in a third group the dermis is rather 

 coarsely shagreened and on the dorsum of the segments are large, 

 conical warts, and similar at the sides or here they are developed 

 into conical filaments; the short bristles and the conical warts or 

 filaments, which answer to each other, are present in the same 

 number and arranged quite in the same way as described above for 

 Platychirus and Lasiophthicus ; there are consequently on the meso- 

 and metathoracal segments six in a transverse row, besides a couple 

 at the side; on the first abdominal segment there are likewise six, 

 placed on one corrugation, and on the next six segments two in the 

 middle on one corrugation and two at each side on the next cor- 

 rugation, and on all seven abdominal segments three on each side; 

 each segment shows four corrugations devided by furrows, and the 

 bristles or warts are placed on the two middle corrugations of each 

 segment. The anterior spiracles are small, lying on each side of the 

 prothoracal segment; the posterior spiracles are placed above on 

 the las" segment on a short, slightly longitutinally devided pro- 

 cess, more or less elliptical in a, transverse section. The mouth is 

 provided with hooks and the head is much retractile and able to 

 be stretched out, and the whole body is likewise very contractile, 

 so that the larva may alter its shape to a rather high degree; when 

 fully stretched out it is long, broad and flat, when contracted it is 

 much shorter, higher and narrower. The colour varies; it may be 

 yellowish, yellowish-grey, grey, reddish-grey or darker, generally 

 more or less marmorate from darker designs and often with one or 



