446 Syrphidae. 



wise the venation is similar to that in Eristalis\ the basal part of the 

 radial vein has fine bristles but often so delicate that they are difficult 

 to detect. Stigma either elongated and with no or an indistinct 

 stigmaticai cross-vein, or the stigma consists only of a cross-vein. 

 Thoracai squamula with long, elegantly branched hairs, alar squamula 

 with longish, curiously flattened hairs; the hairs in the fringes are 

 more or less densely placed in the various species and the squamulæ 

 show otherwise some differences; in the large species {Helophilus s. str.) 

 the thoracai squamula is the larger, it is somewhat inflated inwards 

 at the scutellum as in Eristalis, and it is hairy above on a part near 

 scutellum ; the fringes are very dense ; in the other species the thoracai 

 and alar squamulæ are about equal in size, the thoracai squamula is 

 not inflated, not haired above and the fringes generally less dense. 

 Plumula with branched hairs. ^ 



The developmental stages have long been known, already Linné 

 and Reaumur were aquainted with them ; they are, however, not well 

 known and only few species have been bred. Reaumur (Mém. Ins. 

 IV, 1738, PI. 31, fig. 9—11) mentions a species, probably the common 

 H.pendulus. Meigen (Syst. Beschr. III, 1822, 374) mentions that the 

 larva of H.pendulus lives in putrid water and is similar to the larva 

 of E. nemorum. According to Brauer Riley has mentioned the larva 

 of the American species laMfrons (Amer. Entomol. II, 142). I have 

 myself examined puparia of H. transfugus; the pupæ were found in 

 flood refuse in a fen in April and May; and I have examined larvæ 

 of H. groenlandicus or horealis from Greenland. The larva and pupa 

 are in all respect similar to those of Eristalis, and at present no 

 distinguishing characters have been found between the larvæ of these 

 two genera. The larvæ also live in stagnant and putrid waters in 

 quite the same way as the Eristalis-larYa. The larvæ are, like the 

 Eristalis-\a.r\æ, very tenacious, Wilcox (Anat. Anz. XII, 1896, 278) 

 mentions a larva (it is termed a Belophilus-lsiYya. but may for the 

 rest as well have been the larva of some other Eristalin), which lived 

 at the shore in pools with salt water, and which was able to live in 

 various killing fluids for many hours. Several of the species have 

 probably more than one brood in the year. 



The species of Helophilus are beautiful flies, especially the large, 

 bright species; some of the dark, northern (not Danish) species are 

 rather Eristalis-\ike. The species occur in marshy districts, in fens 

 and at horders of water, and frequent especially Umbelliferæ and also 



^ Girschner says "einfach behaarl" but the species I have examined have the 

 hairs on plumula very distinclly ]»ranched. 



