384 Tachinidae. 



velvet black or brownish black. Frontal bristles descending fully 

 to middle of the cheeks with about four or five bristles. Vibrissæ 

 ascending more or less upwards, but not reaching the frontal bristles. 

 Orbits with fine, sparse hairs, denser and longer above; jowls with 

 longish black hairs. Occipiit yellowish grey, with dense yellow hairs. 

 Antennæ black, second joint may be a little pale at apex, third 

 joint twice as long as second or a little more; arista thickened in 

 about basal half. Palpi yellowish, darker at base. Thorax black, 

 slightly shining, greyish or yellowish grey pruinose, with four some- 

 what broad black stripes, the median not abbreviated until quite 

 behind; scutellum more or less to quite reddish brown. Thorax 

 black-haired; four postsutural dorsocentrals. Abdomen black, some- 

 what shining, sometimes a little reddish at the sides; the three last 

 segments with broad greyish or greyish yellow pruinose bands, a little 

 shifting according to view, the hind margins and a generally narrow 

 middle line black. Abdomen black-haired with only marginal bristles, a 

 pair on second and third and a row on fourth segment. Genitalia small; 

 upper forceps forming an elongated, blade-shaped lancet with a little 

 claw at apex; it is curved ventrally; the upper surface is hollowed 

 and strongly carinate along the middle, and it is covered with longish, 

 backwards directed hairs; arms of lower forceps shining, scale-like 

 pieces at base of upper forceps, their inner anterior corner drawn 

 out in a medium-long style. Legs black. Wings slightly tinged, a 

 little yellowish at base; veins brown; a distinct costal spine. Squa- 

 mulæ yellowish with the margin yellow. Halteres brown to blackish. 



Female. Similar; frons somewhat broader. 



Length. The size may vary very much, the length from 6 to 14 mm. 



T. larvarum is somewhat common; it is known from Sealand, 

 Langeland, Lolland and Jutland; the dates are ^o/^ — ^[^. Nielsen has 

 (Entom. Medd. 2, IV, 1909, 60, and correction ibid. 1913, 372; 

 Vidensk. Medd. fra Dansk naturh. Foren. 64, 1913, 222 and as vidua 

 235) treated its biology; he mentions it from Spilosoma lubricipeda, 

 Malacosoma castrensis, Zygaena lonicerae and Macrothylacia rubi, and 

 further it is found in his collection from Cosmotriche potatoria, Orgyia 

 antiqua and Acrom/cta auricoma, the latter not hitherto known as 

 host for it. In the Zygaena larva from one to four parasites developed. 

 The parasite pupated almost always in the host, only rarely the pupa 

 was found in the cocoon. The species has two yearly broods, in the 

 Zygaena the first brood developed, the imagines came in June and 

 July; in Spilosoma it was the second brood which developed, the 



