Chi'ysotoxum. 57 1 



segment it is so broad that only a narrow, black transverse stripe is 

 left, and the yellow hind margin is sometimes produced triangularly 

 forwards into the interruption of the band ; sometimes the black band 

 almost disappears, the segment then being nearly quite yellow. Ab- 

 domen is clothed with somewhat short hairs, which to a great degree 

 follow the ground colour but generally are black on the yellow hind 

 margins, but sometimes yellow on all hind margins; the yellow hairs 

 are longer and more erect than the black ; the hairs at the side margin 

 are somewhat long, longest at the basal corners; they are yellow, 

 though black just inwards on the black parts. Genitalia red, very 

 large, with large, unsymmetrical appendages. Venter black, shining, 

 with transverse, yellow side spots on second, third and fourth segments 

 towards the front margins and with yellow hind margins to the seg- 

 ments; the side spots are in shape just reversed to the dorsal bands, 

 as they have a concave margin in front and a convex behind; the 

 hairs on venter long, yellow. Legs yellow, the femora more reddish, 

 with the basal part or basal half black; the anterior tibiæ and the 

 basal part of the hind tibiæ of a beautiful pale or canary yellow 

 colour; the legs are haired in the usual way; the short hairs on the 

 anterior side of middle and hind femora more or less black, for the 

 rest the hairs yellow or some black hairs behind the apical part of 

 the anterior femora. Wings a little tinged, more strongly and brownish 



Fig. 193. Wing of C. cautuni c?. 



yellow towards the anterior margin; cubital vein with a slight curve. 

 Squamulæ whitish yellow with a yellow margin and fringe. Balteres 

 yellow. 



Female. Vertex and frons broad, very widening downwards, 

 black, the frons with two large, grey dust spots; the hairs black. 

 Legs paler than in the male, the anterior femora black only at the 

 base, hind femora quite yellow or black only at the extreme base. 



Length 12—14 mm. 



C. cautum is common in Denmark ; Amager, Ermelund, Hareskov, 

 Geel Skov, Søllerød, Hillerød, Tyvekrog, Tisvilde, at Sorø; on Lolland 



