162 Syrphidae. 



marginal cross-vein ciirved above, the upper angle rectangular or a little 

 obtuse. Squamulæ yellowish with a yellow margin and fringe. Balteres 

 pale yellow, the knob more or less darkened to blackish. Plumula 

 rather long-haired. 



Female. Frons broad, almost not widening downwards, with 

 slight lateral and sometimes also a middle channel; it has rather long, 

 erect, yellow hairs. Antennæ with the third joint a little larger than 

 in the male. Abdomen shining and generally more bluish or cyaneous 

 than in the male. The hairiness of the body nearly as long as in the 

 male, on thorax generally more brilliant decply yellow, and more black 

 at the end of abdomen, the whole fourth and fifth segments black- 

 haired and the black hairs at the sides stretching in on third segment. 

 Legs paler, tibiæ yellow, anterior tibiæ sometimes with faint rings; 

 hind femora with stronger hairs below about as in the male. Wings 

 more yellow, especially at the base. 



Length 10,5— 12 mm. 



Remarks: This species varies somewhat with regard to the colour 

 of the hairs at the end of abdomen ; Schiner and Becker say that the 

 male has here no black hairs, while Verrall states, that such are gener- 

 ally but not always present; the female has the end of abdomen 

 black-haired to a smaller or larger extent, and according to Becker 

 in rarer cases quite yellow-haired. All Danish specimens have in the 

 male the end and sides of fourth segment more or less black-haired, 

 and in the female the fourth and fifth and the hind margin of the 

 third segment black-haired. 



C. grossa is not common in Denmark, and has hitherto only been 

 taken in North Sealand and on Lolland; Ordrup Mose, Ermelund, 

 Geel SkoY and Ryget Skov at Farum Sø; on Lolland in Kældskov. 

 My dates are ^''/4 — '^/s; it is exclusively a spring species and it occurs 

 on spring flowers as Caltha in fens and meadows, and I have also 

 taken it on the flowers of Salix; on ^^U I saw it hovering rather high 

 in the air near Salix and other spring-flowering trees, and the sexes 

 sought each other in the air; at the same time some were seen on 

 the flowers of Salix together with numerous specimens of an Andrena^ 

 to which the Chilosia was rather similar. 



Geographical distribution: — Northern and middle Europe down 

 into France, and also recorded from Italy; towards the north to 

 northern Sweden, and in Finland. 



17. C. albipila Meig. 



1838. Meig. Syst. Beschr. VII, 125, 9. — 1862. Schin. F. A. I, 288. 

 — 1894. Beck. Nov. Aet. Leop. Garol. Akad. LXII, 414,68. — 1901. Verr. 



