360 Descriptions of British Diptera. 



Genus TABANUS. 



Antennae as long as the head., approximating at the base curved 

 outwards anteriorly, three-jointed ; first joint thick and cup-shaped, 

 second, small and depressed, third, large and thick, imperfectly 

 crescent-shaped at the base, and narrowing gradually to a point, 

 the upper portion divided into four distinct rings, (Fig. 2 ;) trunk 

 horizontal in the male, perpendicular in the female : palpi con- 

 spicuous and exserted, two-jointed, first joint short and clothed 

 with long hairs, second capitate in the male, long and attenuated in 

 the female, (Fig. 1, a) ; labium large, fleshy, and cylindrical, termi- 

 nating in two long hollow lobes, (Fig. l.g.) ; labrumlong, lanceolate, 

 acute, (Fig. 1st. b.) mandibles and maxillae (the latter wanting in 

 the male,) lanceolate and slender (Fig. ] . c. and d.) ; tongue narrow 

 and pointed, (Fig. 1 e.) ; head transverse, as broad as the thorax, 

 rounded anteriorly, but flattened and somewhat concave behind, and 

 attached to the thorax by a short slender neck : eyes contiguous in 

 the male, a little remote in the female; the facettes largest on the 

 upper side in the former sex : ocelli wanting ; thorax ovate qua- 

 drate ; abdomen inclining to conical in the male, wider and de- 

 pressed in the female ; wings half-open when at rest, furnished 

 with three discoidal cells ; winglets large and circular : tarsi with 

 the radical joint longest, the pulvilli conspicuous, and distinctly 

 three-lobed. 



The Tabani are known in this country by the names of Breeze 

 and Horse-fly. They appear to be the insects called QLstrus by 

 the Greeks, and Asilus by the Romans, and are frequently alluded 

 to under these names by the ancient poets on account of the terror 

 they occasioned among cattle. They are of strong and robust forms, 

 generally somewhat above the middle size, one of the species being 

 the most bulky of the European Diptera. The prevailing colours 

 are somewhat obscure, with the exception of the eyes, which are of 

 great brilliancy, and often ornamented with rays and spots of crim- 

 son and purple. They first appear in the month of June, but are 

 seldom in full force till the middle of autumn. They delight in 

 warm and sultry weather ; are most active on the wing during the 



