Winthemia. 



373 



in basal third. Palpi yellow, more or less darkened at base, rather 



densely hairy at apex. Thorax black, slightly shining, distinctly 



bluish grey pruinose, palest at the sides; there are foiir about equally 



broad, distinct, black stripes, the middle abbreviated behind; further 



a narrow median stripe generally more or less visible; scutelliim 



brownish. Thorax black-haired. Two sternopleural bristles. Abdomen 



black, slightly shining, with a red spot on each side over second, 



third and fourth segment, and apex red; from the third segment 



abdomen is whitish or a little yellowish pruinose, 



especially towards the front margins, shifting with 



dark spots according to view; along the middle there 



is a distinct, narrow, black stripe, widening on third 



segment. Andomen black-haired; second segment with- 



out or with a pair of generally weak bristles, third with 



one or two pairs of marginal bristles and fourth with a 



row of marginal. Fifth sternite small and mostly hidden, 



cleft to base, with a small triangular tooth in the middle 



of inner margin. Genitalia small and hidden; upper 



forceps strong, deeply cleft at base and the corners 



drawn long out and hairy; the apical part elongated 



triangular, curved a little inwards and with a median 



fissure apically; arms of lower forceps likewise «ome- 



what triangular, but with a dilatation in the middle 



of anterior margin; they are not quite as long as upper 



forceps. Legs black; anterodorsal row of bristles on 



hind tibiæ dense, with or without a longer bristle. 



Wings clear or nearly, more or less blackish at base; 



veins black or blackish; first posterior cell narrowly 



open. Squamulæ white. Halteres brownish or yellow. 



Female. Similar; frons as broad as the eye; one 

 or two upper frontal bristles reclinate. Antennæ with third joint 

 broader. Abdomen without or with only small, red side markings. 



Length. Rather varying in size, the length from 5 to 10 mm. 



W. quadripustulata ig common in Denmark on all suitable loca- 

 lities; it occurs in and at woods, in low herbage and on flowers and 

 leaves, but the female is rare ly met with; the dates are ^^/s — ^/g; 

 I have taken it in copula on ^^/g. It is, I think, our most common 

 Tachinid, and occurring during the whole season. It is parasitic on 

 a great number of Rhopalocera and Heterocera. Nielsen has (Vidensk. 

 Medd. fra Dansk naturh. Foren. 68, 1917, 27) treated its biology, 



Fig. 84. 

 W. quadri- 

 pustulata, rj , 

 hind tibia 

 with 

 anterodorsal 

 bristles. 



