Gonia. 393 



Female. Similar; second antennal joint longer and third shorter, 

 the two joints nearly equal. 



Length 11,5 — 13 mm. 



G. capitata is not rare in Denmark; Dyrehaven, Lyngby Mose, 

 Ørholm, Hillerød, Humlebæk, Sletten, Lave Skov near Helsingør, 

 Tisvilde; on Lolland at Strandby and Øster Ulslev; on Funen at 

 Ringe near Faaborg; the dates are ^/g — ^/s- It often occurs in sandy 

 regions, and I have taken it on Thymus and Achillea. The species 

 is parasitic on Agrotis segetum, and also recorded from A. praecox, 

 but this record is uncertain, as the fly possibly was ornata or the 

 Agrotis was segetum. One of my specimens is likewise bred from 



A. segetum, the imago coming on ^Z,. 



Geographical distribution: — All Europe and down into North 

 Africa, and on the Canaries; towards the north to southern Sweden. 

 Also occurring in North America. 



2. G. ornata Meig. 



1826. Meig. Syst. Besclir. V, 3, 2. — 1888. Kow. Wien. Ent. Zeitg. VII, 

 11, 12. — 1907. Kat. palåarkt. Dipt. III, 365. — 1921. Baer, Zeitschr. f. angew. 

 Ent. VII, 363. — 1924. Stein, Arch. f . Naturgesch. 90, 6, 120, 10. — Reaumuria 

 capitata 1830. R. D. Myod. 80, 1. — 1862. Schin. F. A. I, 443 (Gonia). — 1889. 



B. B. Denkschr. Akad. Wiss. Wien, LVI, 100, Tab. IV, Fig. 75 (Gonia). — 

 G. lateralis Zell. 1842. Isis, 843, 2. — 1844. Zett. Dipt. Scand. III, 1194, 2. — 

 Reaumuria melanura R. D. 1830. Myod. 81, 4. — 1838. Meig. I. c. VII, 245, 11 

 (Gonia). — 1888. Kow. 1. c. VII, 14, 7 (Gonia). 



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

 shape and colour; the bristles on orbits outside the frontals somewhat 

 arranged in a row. The hairs on cheeks rather strong, especially 

 downwards. Thorax quadratic, more brownish black and brownish 

 pruinose than in capitata, and more obscurely reddish at the sides. 

 Abdomen red, not yellowish red, the median stripe broader and fifth 

 segment sometimes all black; the pruinose bands more distinct, 

 broader, and whitish also on fifth segment. Legs and wings as in 

 capitata, but the apical cross-vein more straight and the angle less 

 rectangular. 



Female. Likewise similar to the female of capitata, but the 

 hinder half or more of fourth and all the fifth segment black, so that 

 abdomen has the apical part largely black. Thorax more greyish 

 pruinose than in male. 



Length. The species is distinctly smaller than capitata, the 

 length 8,5 — 11,5 mm. 



