Actia. 459 



middle; abdomen is black-haired ; second segment withoiit bristles, 

 third with a pair and fourth with a row of marginal bristles; on 

 second and third segment the hairs along the margin long and thus 

 similar to bristles, but less erect. Legs black to brownish. Wings 



Fig. 95. Anterior part of wing of A. nudibasis. 



nearly clear, a little yellowish at base; veins brown; first posterior 

 cell open, ending at apex of wing; posterior cross-vein in the middle 

 between medial cross-vein and angle; anal vein not reaching margin; 

 gubcostal vein with bristles on outer half, cubital vein to somewhat 

 from the end and postical vein to near posterior cross-vein ; the bristles 

 on subcostal vein short and dense; on the underside of subcostal 

 vein there may be no or more or fewer small bristles. Squamulæ 

 yellowish. H alteres yellow. 



Female. Similar, with frons of the same breadth or very slightly 

 broader; third antennal joint relatively shorter and of the same 

 breadth in the whole length. 



Length 4,5 — 5,5 mm. 



A. nudibasis is not common in Denmark, and only known from 

 Tisvilde and Husby plantation. Nielsen has (Vidensk. Medd. fra 

 naturli. Foren. 1911, 17) treated its biology, but wrongly determined 

 it as pilipennis; he bred it from Evetria resinella and huoliana\ only 

 one parasite develops in each host; the parasite larva bores out of 

 the host larva or pupa and pupates in the gall of the host ; the species 

 has at least two yearly broods, the first was bred from resinella in 

 May and June, the second from huoliana in July. Also Stein mentions 

 it bred from E. resinella. 



Geographical distribution : — Denmark, Germany and according 

 to a communication from Dr. Villeneuve al^o in France; probably 

 generally confused with pilipennis. 



2. A. pilipennis Fall. 



1810. Fall. Vet. Acad. Handl. XXX, 275 et 1820. Dipt. Suec. Muse. 18, 35 

 p. p. {Tachina). — 1824. Meig. Syst. Beschr. IV, 352, 196 {Tachina) et 1838. 

 VII, 243, 8 {Thryptocera). — 1844. Zett. Dipt. Scand. III, 1045, 37 {Tachina). 

 — 1862. Schin. F. A. I, 519 (Thryptocera). — 1894. Pand. Rev. Entom. XIII, 



