Syrphus. 267 



•or it may be narrow and relatively long, with parallel sides; in some 

 species it is intermediate between these two forms. The ventral seg- 

 ments as a rule distinctly chitinised. In the male there are five not 

 transformed dorsal segments, the first and fifth small, the three middle 

 of about equal length, and there are five similar ventral segments, 

 the fifth often partly concealed under the genitalia and in reality not 

 qiiite symmetricai. The genitalia small or medium-sized, rarely rather 

 large; they are of the usual shape, turned to the right; on the ventral 

 side the transformed sixth to ninth segments are distinctly visible 

 (flg. 5). In the female abdomen has six visible segments, but the 

 sixth small, often more or less, or quite hidden; the following are 

 retracted and hidden, the last ending with two small lamellæ. Legs 

 simple, generally somewhat slender; hind tibiæ with the usual slight 

 incurvation on posterior side before the apex; rarely the hind meta- 

 tarsi a little thickened. The legs are haired as usual, with long or 

 somewhat long hairs behind and below the anterior femora and on 

 the anterior side of and below the hind femora, for the rest short- 

 haired; sometimes the hind tibiæ a little fringed above. Glaws and 

 pulvilli well developed ; empodium short, spine-shaped, hairy. Wings 

 with the medial cross-vein well before the middle of the discai cell; 

 cubital vein slightly curved or almost straight, in a few cases {annu- 

 lipes, lapponicus) with a distinct curve about as in Didea, but slighter ; 

 vena spuria distinct, with a nodule below the base of the cubital 

 vein. Alula large. Alar squamula with short, somewhat broad hairs, 

 thoracai squamula with long, branched hairs; in a few species (of the 

 ribesii-^vou^) the thoracai squamula with long hairs on the surfaces. 

 Plumula well developed, with plumulose hairs. 



As remarked the genera from Leucozona to Lasiophthicus are all 

 more or less nearly related to Syrphus, and under each I have given 

 the distinguishing, more or less valuable characters; the most nearly 

 allied genera are no doubt Ischyrosyrphus and Lasiophthicus, and 

 they are, I think, not in reality generically distinct from Syrphus. 

 Leucozona and Eriozona are rather well distinguished, and likewise 

 Didea; for the latter the loop of the cubital vein gives a distinguishing 

 character, and likewise the want of a fringe below the margin of 

 scutellum ; now two Danish species of Syrphus have a distinct curva- 

 ture of the cubital vein, viz. annulipes and lapponicus, but it is, how- 

 ever, less deep than in Didea, especially in lapponicus; with regard 

 to annulipes there is the curious faet that this species has no distinct 

 fringe below the margin of scutellum, about as in Didea, and I am 

 not sure whether it was not naturally placed in Didea; it has, how- 

 ever, not the characteristic shape of Didea, especially not the flat 



