DIPTERA, Q1 
than the chest; palpi black: feelers black ; compound joint rather short, 
spindle-shaped for most of its length, but suddenly tapering towards the 
tip: abdomen elliptical, a little longer and broader than the chest; hind 
borders of the segments, and sides of the first and second segments, tawny : 
legs black; thighs thinly clothed with tawny hairs; shanks and feet 
clothed with short black hairs; shanks dark tawny towards the base ; foot- 
cushions tawny: wings slightly gray ; wing-ribs tawny; veins black, 
tawny towards the base; tip cross-vein almost straight, having only a very 
slight downward curve along most of the length; posterior submarginal 
areolet very open to the border; poisers black. Length of the body 44 
lines ; of the wings 9 lines. 
Cape. 
TABANUS, Linn. 
The study of these insects is connected with that of quadrupeds, and 
comprises a knowledge of the distribution, introduction, diffusion, diminu- 
tion and extinction of the Ruminants and of some other groups. The 
species of Tabanus are generally local, but as a genus it extends nearly 
over the world, and both the reindeer and the camel are its prey. In 
many regions it has not as yet been observed, and consequently its geo- 
graphy and the relative proportion of species in the various continents 
and islands is comparatively unknown. Some parts of the structure are 
very variable in form, especially the third joint of the feelers and the tip 
cross-vein which divides the submarginal areolets; these variations are 
too numerous and too gradual to be regarded as characters of groups 
or of subgenera, but their succession and limits may be exhibited by 
a tabular series of the species, or by means of curved lines in diagrams. 
The third joint of the feelers in some species is slightly convex above, in 
others it is armed with a long horn, and no link is wanting between these 
two forms. The fourth and following joints form a compound joint which 
varies much in length, and is either straight or curved upward, stout or 
slender. A curve near the base of the tip cross-vein has very frequently a 
tendency to assume an angular form, which is very rarely a right angle, 
but generally more or less obtuse. It is often accompanied by the stump 
of a vein, which is long in proportion as the angle whence it springs is 
more distinct and less obtuse, or, in other words, the two veins incline 
more or less to be blended into one. In New Holland and New Zealand 
