Myiatropa. 469 



triangular, black middle stripe on the front part; the hind margins of 

 the segments more grey but less or not shining. The anterior knees 

 more orange. 



Length 10,5—12,5 mm. 



H. vittatus is very rare in Denmark, only three specimens have 

 been caught, a male and two females, all on Amager; a male and a 

 female were taken on ^'^/t and ^/s 1909 (J. C. Nielsen) and a female 

 on ^^/s 1915 (Klocker); they were flying rapidly but lovv over a ditch 

 vjiih water and rich herbage. 



Geographical distribution: — Middle Europe down into Austria; 

 it has its northern limit in Denmark, and occurs in England. 



31. Myiatropa Bond. 



This genus in nearly related to Eristalis and Helophilus and 

 stands intermediate between them. The eyes are hairy and touching 

 in the male. Antennæ inserted in the middle of the head, third joint 

 oval; arista long, apparently bare. Epistoma a little hoUowed below 

 the antennæ, with a moderate central knob and retreating to the 

 mouth edge; it is thus not produced, a little descending; it has a 

 black, bare middle stripe. Thorax with curious, pale pruinose, trans- 

 verse markings, more or less distinct. Abdomen rather broad, with 

 yellow markings, similar to those in Helophilus, but with pruinose 

 spots only on the last, or (in the female) on the two last segments. 

 Genitalia of medium size. Legs simple, hind femora not thickened; 

 the curious hair above on the trochanters present. Wings as in 

 Helophilus with the subcostal cell open; I find no distinct hairs on 

 the basal part of the radial vein. Stigma mainly consisting of a thick 

 cross-vein. Squamulæ as in Eristalis. Plumula of a curious shape, 

 divided into branches from the base, and with branched hairs. 



With regard to the developmental stages De Geer suspected (Mém. 

 Ins. VI, 1776, 101) that the larva belonged to the rat-tailed form, as 

 he had seen the flies sitting on the mud as for depositing the eggs. 

 Beling (Verh. zool. bot. Gesell. Wien, XXXVIII, 1888, 4) describes the 

 larva and pupa (H. nigrotarsatus) ; he found one larva and six pupæ 

 in decaying wood on a beech {Fagus) on '^^U, the imagines came 

 i!»/5 — 2^/5; another pupa was found under similar circumstances on 

 '^^/4, it developed on ^Vs. I have myself examined larvæ taken at a 

 fen in a tree-stub with water on ^^/4, they developed on ^'^/s, a pupa 

 taken in a tree-stub with water on ^^/4, developing on ^Vs, and another 

 pupa taken at a ditch on ^/s and developing on ^^/o. — The larva is 

 quite similar to that of Eristalis, perhaps a little more flattened; the 



