4^ 
Colonel Yerbury and Mr. W. R Ogilvie Grant took, in addition to 
the normal male already mentioned, three females of the bisignatus 
form. In many of the females in the Museum collection there is no 
trace of the russet markings on the sides of the second abdominal 
segment seen in the specimen shown in the plate, but the abdomen 
appears wholly black, with, however, a longitudinal row of whitish 
markings on each side of the median series of white triangles. The 
resemblance between the form bisignatus and Therioplectes micans, 
Mg., has already been alluded to in the notes on the latter species 
(see page 37). 
The two males of Th. tropicus referred to above are 14! mm. in 
length, with a wing-expanse of 28 mm. ; the length of the females 
varies from 14 to 15! mm. According to Brauer (loc.cit, pp. 146-147) 
the eyes in this species are green with three purple bands ; in the 
male the lower margin is green and unbanded. The Museum pos- 
sesses no specimens of this species from Wales, Scotland, or Ireland, 
but in England at any rate TJi. tropicus appears to be among the 
more common of the larger horse-flies. The dates of capture of the 
females in the Museum series range from May 16th to July 12th inclu- 
sive, and the localities are Brinklow, Warwickshire (E. E. Austen) ; 
Berkhamsted, Herts ( IV. R. O. Grant) ; Felden, Boxmoor, Herts 
{A. Piffard); Colchester, Essex (W. H. Hariuood) ; Oxshott, Surrey 
( W. R. O. Grant and Lieut-Colonel Yerbury) ; and New Forest, Hants 
{Lieut.-Colonel Yerbury and C. O. Waterhouse). In the last-mentioned 
locality Colonel Yerbury notes that bisignatus is the common form of 
the species. Continental specimens of 77/. tropicus in the Museum 
collection are from Siberia, Norway and Russia (typical form), and from 
Rhenish Prussia (form bisignatus). Additional Continental localities 
given by Brauer are Sweden, Germany and Austria for the typical 
form, and France, Silesia and Asiatic Russia for the form bisignatus, 
which was originally described from a specimen from the neighbour- 
hood of Paris. 
