270 Tachinidae. 



Hareskov, Bagsvær, Ryget Skov, Ruderhegn, Donse, Humlebæk; 

 on Lolland at Saxkøbing and in Høvænge Skov near Nysted; on 

 Funen at Odense and Veflinge; on Taasinge; in Jutland at Sønder- 

 borg, Madeskov, Kollund, Sandager, in Greisdal, at Nebsager near 

 Horsens, at Horsens, Ry and Hattenæs near Silkeborg, Frijsenborg, 

 Gerlev near Randers Fjord and Skørping, and finally on Bornholm 

 at Rønne and in Almindingen; the dates are ^^/g — ^^/g. It occurs on 

 bushes and in low herbage at the outskirts of woods and in fields. 

 The species is parasitio on larvæ of M. vulgaris and R. solstitialis ; 

 Boas has (Entom. Medd. V, 1893, 130) treated its biology; he found 

 the larvæ in larvæ of M. vulgaris which were two and three years 

 old ; the parasite was present in a number of one to three in the host, 

 and they lay free in the fat body, not sitting in any funnel; the larva 

 hibernates in the host, it bores out and pupates in the ground, and the 

 imago develops in June and July. 



Geographical distribution: — Europe; towards the north to 

 middle Sweden, and in Finland. 



2. D. vacua Fall. 



1816. Fall. Vet. Acad. Handl. 240, 10 et 1822. Dipt. Suec. Muse. 42, 10 

 (Musca). — 1826. Meig. Syst. Beschr. V, 46, 23 et 1830. VI, 374. — 1844. Zett. 

 Dipt. Scand. III, 1265, 3. — 1862. Schin. F. A. I, 560. — 1896. Pand. Rev. 

 Entom. XV, 160, 9. — 1907. Kat. palåarkt. Dipt. III, 446. — 1921. Baer, 

 Zeitschr. f. angew. Entom. VII, 380. — 1924. Stein, Arch. f. Naturgesch. 90, 6, 

 238, 2. 



Male. This species is much like the preceding. Head of same 

 shape and colour and with the same bristles. Antennæ with third^ 

 joint longer, thrice as long as second or about. Thorax coloured as 

 in rustica, but with generally only the middle pair of præsutural 

 and the præscutellar pair of postsutural acrostichals, and generally 

 only two sternopleural bristles; one posthumeral and two intraalar 

 bristles. Abdomen more slender, less pruinose and more clear yellow, 

 with a brown middle stripe which is incised or interrupted at the 

 incisures, and the hind margin of fourth segment black; bristles as 

 in rustica. Legs and wings as in rustica. 



Female. Of a somewhat different aspect. Frons broad. Abdomen 

 black, somewhat shining, the three last segments with a broad greyish 

 or yellowish white silvery front band; discai bristles present as in 

 male. Wings often rather dark. 



