26 
the sides by the maxillary palpi, which are large and two-jointed. 
The females only are blood-suckers ; in the males the mouth-parts are 
less adapted for piercing, and they live on the sweet matter in 
flowers or on “ sweet sap.” 
The compound eyes are very large, and often, especially in the 
males, nearly cover the head, and are frequently gaily patterned 
{whilst living) with spots or stripes of bright colours. The third 
joint of the antenna is large, and often with such a decided notch 
as to give a tooth-like projection (see figure of fly, p. 25). The 
ocelli, or simple eyes (mere little spots on the top of the head), are 
said to be usually absent, or almost obsolete, though sometimes, as 
in Chrysops, three are recorded to be present. The thorax (body 
between the wings and to which the legs are appended) is compact 
and thick, with the scutellum {i. e. the small upper hinder portion) 
much developed. The icings rather deflexed, or laid flat, and with 
many veins ; when at rest usually not laid over each other, but 
about a quarter or half open, or extended horizontally. The alulets, 
or winglets (an enlargement of the membrane at the lower part of 
the hinder edge of the wing), large. The abdomen seven-ringed. 
The legs stout. 
The figures of the Great Ox Gad Fly, given at pp. 25 and 27, 
convey a fair idea of the above details so far as they can be shown 
without being very much magnified. 
With regard to the eggs of the Tabanulce, the only information 
which I am aware of as being definitely given is that quoted (as fol¬ 
lows) from Dr. Willeston, in Bulletin No. 5, new series, U. S. Dept, 
of Agriculture, referred to below, in which he says :—“The spindle- 
shaped brown or black eggs are in spherical or flat groups, stuck 
together and attached to the leaves or stems of grasses and other 
plants ; those of the aquatic larvae are fastened to rushes. . . . The 
young larvae are known to penetrate beetles or other larvae, and 
remain within them till they have completely consumed them, and 
their enlarged bodies have filled out the skins.” (Stand. Nat. Hist, 
vol. ii. p. 417.)* 
The larva, or maggots, of the family of the Tabanidce do not live 
in or on the hides of horses or other animals; many live in damp 
earth or sand, or under decaying leaves and stems in damp places. 
The T. bovinus (Great Ox Gad Fly) has been reared from maggots 
taken from the earth of a meadow; and the maggot of Tabanus 
tropicus { = Therioplectes tropicus) has been found to feed underground 
in damp woods, from whence the flies greatly tormented the horses 
* “Insects Affecting Domestic Animals,” by Herbert Osborn. ‘Bulletin’ 
No. 5, new series. U.S.A. Dept, of Agriculture, Washington, 1896. 
