Didea. 255 



segments broader, occupying the two thirds of the length of the seg- 

 ments and none of them interrupted (or only in very rare cases and 

 somewhat indistinetly). The genital knob shorter haired than in alneti. 

 The fourth ven tral segment not bluish, but yellow, with a large, black 

 spot at the hind margin. Anterior femora with the black colour ex- 

 tended more towards the apex than in alneti; anterior tibiæ quite 

 yellow, or with very slight indications of rings, somewhat yellow-haired. 

 Wings with the loop of the cubital vein considerably deeper than in 

 alneti, and produced a little more towards the tip of the wing. Balteres 

 with the knob yellow. 



Female. Frons with the black middle line stretching longer down 

 before dividing than in alneti and hence the legs of the furcate spot 

 shorter, and sometimes they are somewhat indistinct. Abdomen with 

 the markings a little narrower than in the male, but broader than in 

 alneti; sometimes the bands extend somewhat over the side margin; 

 the fifth segment with a yellow band or a pair of spots; the last 

 (eighth) segment broader than in the other species. 



Length 11,5 to fuUy 12 mm. 



D. fasciata is perhaps a little less rare in Denmark than alneti; 

 Ordrup Mose (Stæger), Nyrup Hegn (the author), Tisvilde (Klocker, 

 the author) ; on Lolland at Strandby (L. Jørgensen) ; on Funen at 

 Middelfart (Th. Mortensen), and in Jutland at Silkeborg (A. Petersen, 

 Esben Petersen) and at Rebbild near Skørping (Kryger). My dates 

 are '^^le—^h. It occurs in the same way as alneti, perhaps on more 

 dry localities, and I think it frequents especially Gompositæ as Hiera- 

 cium, but it has also been taken on flowers of Sambucus. 



Geographical distribution : — Europe down into Italy, towards the 

 north to southern Sweden; according to Aldrich it also occurs in 

 North America (fuscipes Loew). 



3. D. intermedia Loew. 



1854. Loew, Neue Beitr. II, 18, 39. — 1862. Schin. F. A. I, 314. — 

 1901. Verr. Brit. FL VIII, 331, 3, figs. 275—277. — 1907. Kat. palåarkt. 

 Dipt. III, 55. 



Male. Similar to the two preceding species, especially to fasciata, 

 but smaller and with the yellow markings intermediate with regard 

 to extent. Epistoma with the mouth edge black, and this colour ex- 

 tending up over the central knob; jowls grey. Thorax æneous, with 

 faint purplish reflections (when alive, thorax is distinctly bluish or 

 purplish, but this colour vanishes by exsiccation) ; thorax yellow-haired. 

 Scutellum as in ahieti, with yellow hairs, but black hairs at the margin 



