472 Tachinidae. 



to the end of epistoma; arista brownish, second joint elongated. Palpi 

 yellow, a little elongated. Thorax greyish to yellowish brown prui- 

 nose, palest at the sides; sciitellum of same colour, more or less 

 yellow on apical part. Thorax densely black-haired; four postsutural 

 dorsocentrals, but sometimes the second anterior abortive and thus 

 only three. Sciitellum with a pair of discai bristles more or less devel- 

 oped. Abdomen quite yellow with only a narrow dark greyish middle 

 line, widening behind, or the two last segments are quite or mainly 

 grey. Abdomen is densely black-haired, second segment generally 

 without bristles, but sometimes with one or a pair of marginal bristles, 

 third segment with a pair and fourth with a row of marginal bristles, 

 six in number; also fifth segment with only a marginal row, Genitalia 

 small; upper forceps triangularly beak-shaped, arms of lower forceps 

 of a similar shape and of the same length. Legs yellow, tarsi black. 

 Wings yellowish tinged; veins brown; apical cross-vein concave. 

 Squamulæ whitigh or yellowish white. Halteres yellow. 



Female. Similar; frons of the same breadth; third antennal 

 joint a little shorter. Palpi more elongated and a little dilated to- 

 wards apex. Abdomen with the middle stripe rather widening behind 

 and the two last segments grey, or the three last are quite grey, 

 and in rare cases even the second only shghtly yellow. 



Length 4,5 — 5,5 mm. 



B. cristata is not very common in Denmark; Copenhagen in a 

 garden. Sletten, Roskilde; on Funen at Odense, and in Jutland at 

 Frijsenborg and Aalborg; the dates are ^»/g — 7/g; in Stæger's collec- 

 tion a number of specimens is present, probably from near Copen- 

 hagen; the author remarks that it only occurs in July "tune vere non 

 raro". In my experience it is rather rare. As hosts are recorded Tipula 

 maxima, Pegomyia nigritarsis? and a number of Heterocera, but on 

 account of confusion with maculata the records are scarcely sure. 

 On the Tipula-larvæ, which live in water, the egg is no doubt depo- 

 sited in the moment when the posterior spiracular tube is raised to 

 the surface; the larva bores out when the full grown Tipula larva 

 goes into the ground to pupate ; in the Tipula larva only one parasite 

 was found, while in an Agrotis larva there were several present. 



Geographical distribution: — Northern and middle Europe 

 down into France; towards the north to middle Sweden. 



