THE TANYSTOMA. 359 



established. The most abundant of these is the 

 Hamatopota pluvialis, a dull grey fly rather larger 

 than the common House-fly, with greyish wings 

 mottled with brown. The legs are blackish, with the 

 base of the anterior tibiae yellow, and two rings of 

 the same colour on the posterior and intermediate 

 tibiae. The face, between the eyes and the base of 

 the proboscis, is whitish, with numerous small brown 

 points; above the antennae is a large shining black 

 patch, and above this again a pair of round blackish- 

 brown spots. The antennae are black, and composed 

 apparently of three joints, of which the first is large, 

 thick, and somewhat oval in form, the second small, 

 and the third a good deal longer than the first ; but 

 on close examination the extremity of this is found 

 to be divided into three small joints, so that the total 

 number is six. The eyes are exceedingly beautiful 

 during life, being of a green colour, with three or 

 four waved reddish-brown bands across them; but 

 after death they acquire a uniform brown tint like 

 those of the common House-fly. This fly is found 

 abundantly in the summer about pastures, where it 

 attacks cattle and horses, and occasionally men, 

 becoming especially active and bloodthirsty before 

 rain. As in the case of the Gnats, it is, however, 

 only the females that exhibit this predilection for the 

 blood of vertebrate animals, the males contenting 

 themselves with the juices of flowers, which are also 

 occasionally imbibed by the females, probably in 

 the absence of their favourite nourishment. In 

 correspondence with this difference in habit, there is 

 a considerable difference in the development and 

 structure of the mouth in the two sexes, the proboscis 

 in the males being small, and containing only four 



