Actia. 461 



to middle Sweden, and in Finland; also recorded from North America, 

 but, as said, probably often confused with nudibasis. 



3. A. crassicornis Meig. 



1824. Meig. Syst. Beschr. IV, 351, 195 {Tachina) et 1838. VII, 243, 6 

 (Thryptocera). — 1844. Zett. Dipt. Scand. III, 1046, 38 {Tachina). — 1862. 

 Schin. F. A. I, 518 (Thryptocem). — 1889. B. B. Denkschr. Akad. Wiss. Wien, 

 LVI, 103, Tab. V, Fig. 88 et 1891. LVIII, 355 {Gymnoparia). — 1894. Pand. 

 Kev. Entom. XIII, 110, 3 {Thryptocera). — 1907. Kat. palåarkt. Dipt. III, 387. 

 — 1920. Villen. Ann. Soc. Ent. de Belg. LX, 66. — 1921. Baer, Zeitschr. f. 

 angew. Ent. VII, 372. — 1924. Stein, Arch. f. Naturgesch. 90, 6, 132, 5. 



Male. Similar to pilipennis. Antennæ black, third joint large and 

 dilated, about five times as long as second; arista thickened in basal 

 half, second joint elongated. Palpi yellow, darkened at apex. Thorax 

 grey, with at most an indication of two narrow darker stripes in 

 front. Scutellum pale just at apex. Three or four postsutural dorso- 

 centrals. Abdomen as in nudibasis, with similar bristles. Legs black. 

 Wings as in pilipennis, subcostal vein likewige with long, not dense 

 bristles in whole length, but the underside not bare, but with bristles 

 in apical half; anal vein not reaching margin. Squamulæ whitish or 

 slightly yellow. Halteres yellow. 



Female. Similar; antennæ reddish at base, third joint shorter 

 and not dilated. Abdomen much more grey, as the bands are broad, 

 leaving the hind margins and a middle stripe black. Front tarsi a 

 little dilated towards apex, fifth joint considerably longer than fourth. 



Length 4 — 4,5 mm. 



A. crassicornis is rare in Denmark, only six specimens, one male 

 and five females, are known; Lersø (Stæger) and in Jutland at Silke- 

 borg (Esben-Petersen), Laven (H. J. Hansen), Hov and Thisted 

 (the author); the dates are ^Z, — ^"/g. The species is known bred from 

 Evetria resinella and buoliana, Tortrix viridanå, Depressaria applana 

 and the non Danish Heijdenii. 



Geographical distribution: — Europe; towards the north to 

 Southern Sweden, and in Finland. 



I 4. A. frontalis Macq. 



1845. Macq. Ann. Soc. Ent. de Fr. 2, III, 289, 7, Tab. VI, Fig. 3 {Thrypto- 

 cera). — 1862. Schin. F. A. I, 518 (Thryptocem). — 1907. Kat. palåarkt. Dipt. 

 III, 388. — 1921. Baer, Zeitschr. f. angew. Ent. VII, 372. — Roeselia lamia 

 Meig. 1838. Syst. Beschr. VII, 254, 4. — 1844. Zett. Dipt. Scand. III, 1083, 

 80 {Tachina). — 1894. Pand. Rev. Entom. XIII, 110, 5 (Thryptocera). — 1924. 

 Stein, Arcli. f. Naturgesch. 90, 6, 135, 10. 



