Asilidae. 65 



Length 18—26 mm. 



This species is at once distinguished from all otfier Danish species 

 by its bright colour. 



A. crahronifonnis is not rare in suitable localities; Ordrup Mose, 

 Ermelund, Donse, Esrom Sø, Tisvilde, Jægerspris, at Helsingør and on 

 Vallø Strand; on Funen at Odense, Veflinge and Faaborg; in Jutland 

 at Horsens, Dollerup and Hald near Viborg and on Als Odde at 

 Mariager Fjord. It is a somewhat late species, my dates are ^^li~^U. 

 It occurs on dry fieids and on heaths, often in no small numbers, 

 and it is here often seen sitting on horse-dung. It is a very strong 

 robber; its prey is often Acridiids which may be as large as itself; 

 it also catches beetles and flies as recorded by Poulton 1. c, f. inst. 

 Sermyla halensis L., Lucilia cæsar L., Sarcophaga carnaria L., Seri- 

 comyia horealis Fall. and Asilids. 



Geographical distribution: — Most of Europe down into Italy; 

 towards the north to middle Scandinavia and southern Finland; also 

 in North Africa. 



11. Rliadiurgus L6w. 



Species of rather small size and dark greyish colour. Face not 

 broad, widened somewhat downwards, shining black in the middle; 

 epistomal cailus medium sized but very prominent, reaching somewhat 

 more than half the height of the epistoma. Antennæ placed some- 

 what above the middle, the hairs on the under side of the first joint 

 somewhat long. The eye-facets in the front part of the eye distinctly 

 enlarged. Dorsocentral bristles present on the posterior half part of 

 thorax. No bristles at the hind margin of the abdominal segments. 

 Front femora without spine-Uke bristles below. Male genitalia of 

 medium size, somewhat slender, the upper forceps with an incision 

 above at the apex; the ventral lamella pruinose, resembling a venlral 

 segment; penis with the median branch very long. The female ovi- 

 positor short, broadly conical with free lamellæ. 



Of the genus only one palæarctic species is known, also occurring 

 in Denmark. 



1. R. variabilis Zett. 

 1840. Zett. Ins. Lapp. 506. 4 {Asilus). — 1842. Zett. Dipt. Scand. I, 

 169, 5 el 1855. XII, 4565, 5 {Asilus). — 1849. Low, Linn. entom. IV, 133, 68. 

 — 1862. Schin. F. A. I, 157 (Asilus). — 1903. Kat. palaarkt. Dipt. II, 145. 



Male. Eyes, when the species is alive, slightly metallic, brownish 

 ■with a slight greenish cast. Epistoma shining black in the middle, 

 whitish pruinose at the eye-margins; the callus grey; epistomal beard 

 white in the middle, black above with the black hairs going down 



Diptera Danica. II. 5 



