Mr. F. W. Edwards on British Limnobiidae. 201 
letter). With this author's further opinion (also in letter) 
that all these three are mere varieties of D. chorea, I can, 
however, by no means agree. 
D. affinis Schum. This, as mentioned above, may not 
be specifically distinct from D. mitis and D. lutea, but the 
colour differences are so extreme that I prefer to separate 
the three forms. D. affinis seems to be very common in 
hilly districts (Scotland and Welsh borders) and also in 
the New Forest. It is the species recorded as D. stigmatica 
by Verrall, and probably also the D. stigmatica of Bergroth. 
Meijere considers that D. affinis is the same as his D. stig- 
matica, but I consider that Schummel’s description applies 
better to the species now under consideration; there 
appears to be no other name applicable to it. 
D. stigmatica Mg. This is really an addition to the British 
list, which I have seen from Newtonmore, Inverness 
(F. Jenkinson), Perthshire (A. FE. J. Carter), and Bonawe, 
Argyll (J. Waterston); it is well distinguished from other 
British species (in the male sex) by the greatly swollen and 
complicated hypopygium. Some discrepancies in the 
figures notwithstanding, de Meijere is probably right in 
regarding the D. stigmatica of Osten-Sacken as the same as 
the species figured by himself, and also D. mnigristigma 
Nielsen. Meigen’s description is inconclusive, but it will 
be as well to follow Osten-Sacken and de Meijere in their 
identification of the species. 
D. autumnalis Staeg. This is the D. mitis Mg., of the 
British list; de Meijere, however, figures it as D. autumnalis 
and remarks that though D. mitis Mg., is hardly recognisable 
without an examination of the type, it is probably not the 
species so determined by Verrall. Probably Verrall him- 
self had doubts on the point, since some of the specimens 
in his collection stood as D. autwmnalis. 
D. halterella sp. n. (PI. I. fig. 1.) 
A species somewhat resembling D. sericala, but smaller, more 
slender, the mesonotum less distinctly striped, and the halteres of a 
remarkable shape. Head dull dark brown; proboscis lighter ; 
antennae and palpi entirely black; flagellar joints all about equal, 
oval, with short verticils not longer than a single joint. Thorax 
dark ochreous-brown, dull, pollinose; pleurae greyer; mesonotum 
with a rather indistinct dark central stripe. Abdomen blackish- 
brown above, pale beneath on the first three segments; hypopygium 
pale, with a very complicated structure (see fig. 1). Legs slender, 
