THE BREEZE FLIES. 85 



scutellum. Beris clavipes, vallata, and clvalybeata are common British species. Among the exotic 

 forms of this group are some South American species of gigantic size ; some of them measuring an 

 inch and a quarter in length. 



TRIBE III TANYSTOMA. 



This third tribe of the Diptera, which includes a considerable number of families presenting 

 a great variety of structure and habits, is distinguished especially by the structure of the mouth, 

 the proboscis being longer than in the preceding tribe, and sometimes very long, and the internal 

 organs more completely developed. Thus the proboscis generally encloses a lancet-like labrum and at 

 least three other setae ; while in one family the females, at least, present all the parts that we 

 have described as forming the perfect Dipterous mouth. The antennae consist of only three joints, 

 usually furnished with a terminal bristle, which may be jointed ; but in one family the bristle is 

 wanting, and the extremity of the third joint is ringed. They differ from the Notacantha, as also 

 from the following tribe, in the nature of the metamorphosis, the larva skin being cast when the 

 insect passes into the pupa state. The larvae are worm-like, but furnished with a distinct head, which 

 bears movable claw-like organs appended to the mouth. They generally live underground. 



FAMILY IX. TABANID^E, OR BREEZE FLIES. 



The insects of this family, which are commonly known as Breeze Flies and Gad Flies, are 

 of a broad, robust form of body, and provided with large and strong wings. They have a broad 

 head, hollowed behind so as to fit close to the thorax, and occupied for the most part -by the 

 compound eyes, which in the males generally meet upon the vertex, and in which the upper or 

 middle facets are larger than the rest. They usually have three distinct ocelli. The antennae are 

 really or apparently three-jointed, but the third joint, which is destitute of a bristle at its apex, 

 and is frequently deeply notched on one side, is usually ringed, either at the apex or throughout. The 

 proboscis is long in the females, shorter in the males, and in the former it encloses the full number of 

 bristles, two of which are deficient in the males. The abdomen is broad, and consists of eight 

 segments ; the tarsi have three pulvilli ; and the wings have a complete central cell, from which three 

 veins run to the hinder margin. 



The Tabanidae are among the finest and most powerful of the Diptera, and the females make 

 use of the formidable apparatus of lancets with which they are endowed for the purpose of 

 sucking the blood of man and animals. They fly about in the sunshine with a buzzing noise, 

 from which the name of Breeze Flies is said to be derived, and alight quite imperceptibly upon their 

 intended victims. Their bite is exceedingly painful, and their attacks are much dreaded by 

 cattle. The males pass their time more quietly, and are usually found resting upon the stems 

 of trees. Some 500 or 600 species are known from all parts of the world. Many of them are 

 remarkable for the beautiful iridescent colours displayed by their compound eyes. 



The preparatory states are passed in the ground, the larvae, which have a distinct head and 

 consist of twelve segments, feeding, it is believed, upon the roots of grasses and other plants. 

 About the month of May the larva is full grown ; it then sheds its skin and becomes converted into 

 a free pupa, having fringes of hairs on the abdominal segments, and a circlet of bristles near the 

 end of the abdomen structures which ai*e of use to the pupa in making its way out of the ground 

 when about to give birth to the perfect insect. This takes place in the summer, and at this season 

 the Breeze Flies are often a source of great discomfort to both man and beast in many parts of 

 the country. The female of the large Ox Breeze Fly lays some four or five hundred eggs upon 

 grass stems, and the larvae are hatched from these in ten or twelve days. 



In England there are several species which are referred to three genera, but most of them 

 belong to the typical genus, Tabanus. The largest of them, and, indeed, one of the largest known species, 

 is the Ox BREEZE FLY (T. bovinus, see figure on p. 86, and PI. 62, D), of which the females measure 

 nearly an inch in length ; but it is not very abundant in Britain. Tabanus autumnalis, one of the 

 commonest species, measures from two-thirds to three-quarters of an inch, and is of a blackish-brown 

 colour, with bronzed brown eyes, and the -rest of the head yellowish- white, the antennae black, the thorax 

 marked with five grey stripes, and the abdomen with five rows of greyish spots. The wings are 

 grey, with a tawny tinge at the base and along the front margin ; the halteres are brown with 



