J Ascriptions of British Diptera. 145 
of tail fourteen inches and a-half. Inhabits the Island of Ceylon, 
and does not appear to have been yet described. 
It is named in honour of the individual who formed the genus, 
and though the form and mode of arrangement of the scales are dif- 
ferent to those of Chrysopelea ornata, yet it is clearly a species of the 
same genus. As far as regards the character of the scales and their 
mode of distribution it is nearly allied to the genus Bucephalus, as 
described by me in one of the numbers of the Zoological Journal. 
2. Chrysopelea Capensis Ch. supra viridi-ccerulea y infra antice 
viridis, viridi-Jlavo umbrata, postice viridi-cosrulea. 
Abdominal plates 216. Subcaudal scales 109. 
Above greenish blue, verging towards a light slate hue ; head tinted 
with purple ; anterior part of belly light green, mottled with green- 
ish yellow, posterior part the same colour as back ; scales large, sub- 
ovate, and disposed in oblique rows, as in the Chrysopelea ornata, all 
of them, as well as the abdominal plates and subcaudal scales, with 
a shining metallic lustre ; eyes brown. Length from nose to anus two 
feet eight inches, from anus to tip of tail eleven inches. The three 
species probably all belong to that class of snakes which generally 
resort to trees to obtain their food, at least the last described was 
killed when turned round the branch of a high shrub, near to the 
mouth of the Orange river. 
As has already been remarked, the scales of the present species 
are arranged as in the one which Mr Boie selected for the type of the 
genus. Their forms also approximate to those observed in it, and thus 
differ in both respects from the Chrysopelea Boieii, found in Ceylon. 
,V. Characters and Descriptions of the Dipterous Insects indige- 
nous to Britain. By JAMES DUNCAN, M. W. S., &c. &c. 
(!N the following series of papers it is proposed to give a list of 
the Dipterous insects indigenous to Britain, with the Generic cha- 
racters, Specific descriptions, and Localities, with as much accuracy 
as it is possible from the materials in the possession of the author. 
This singular and interesting tribe of insects has been hither- 
to comparatively neglected by British entomologists, but several 
valuable continental publications have been devoted to them, and 
in drawing up the characters and descriptions, Mr Duncan has chiefly 
made use ofMeigen'sEuropaischen Zweiflugeligen Insecten, and Mac- 
quart's Insectes Dipteres du nord de la Fratice, works of great pre- 
cision and minute accuracy. We have already to offer our acknow- 
ledgments to several gentlemen, for communications relative to the 
NO. II. K 
