216 STRATIOMYID^> 



Thorax and scntellum with short depressed pale yellow pubescence ; 

 humeri distinctly yellowish. 



Abdomen sometimes nearly all yellowish except for dark triangular spots 

 near the hind corners of the segments, and -with much shorter pubescence 

 at the sides. Genitalia with a pair of terminal orange lamellsB, 



Legs paler than in the male and the hind femora not darkened about the 

 middle, while in pale specimens the hind tibiae are hardly at all darkened ; 

 hind tibiae less dilated, and basal joint of the hind tarsi only a little dilated ; 

 front tarsi occasionally dark to their base. 



Wings slightly more hyaline, and sometimes the stigma only pale bro^vn. 

 Alar squamae yellow with whitish yellow fringes. 



Length about 6 mm. 



This species varies so much in the yellow coloring on the disc of the 

 abdomen as to raise the impression that there might be two species under 

 it, but I am unable to find any definite character for distinction ; it also 

 varies in the intensity of the dark markings on the legs (especially in the 

 female), and in the colour of the frons and the facial pubescence, and I 

 think also that there are slight variations in the narrowing or expansion 

 of the frons and face. There is no close ally known in Europe, as Actina 

 nitens is much blacker and has hairy eyes. 



C. tibialis is not uncommon over the south and middle parts of England, 

 as I have numerous localities from Devonshire, Hampshire, Sussex, Kent, 

 Surrey, Cambridgeshire, Norfolk, Suffolk, Lincolnshire, Wiltshire, Gloucester- 

 shire, Herefordshire, Yorkshire, and Glamorgan, from July 4 to September 

 14. The males often congregate in aerial dances. It is recorded from 

 almost all Europe. The metamorphoses are noticed under the generic 

 description. 



Synonymy. — Meigen originally descrilied his Beris tihiaUs from a male in 

 Baumhauer's collection and a female sent from England by Dr Leach, and no doubt 

 has ever arisen as to their identity. A. Costa in 1857 described an Actina hyalini- 

 ventris of which I have not seen the description, but Bezzi (Bull. Soc. Ent. Ital., 

 xxxii. 77, 1900) wrote of it as a species which has a certain affinity of appearance 

 with C. tibialis and as occurring throughout Italy. I know nothing about the 

 species, but the name suggests the paler form of C. tibialis, and in Bezzi's Band ii. 

 of Kertesz's Katalog it is sunk as a synonym, so that it is to be supposed that Bezzi 

 had become convinced that it had more than a certain affinity of appearance. 



