37 



almost wholly composed of the eyes, which, with few exceptions,* 

 meet together above in that sex, but in the female are separated 

 by the space known as the front, bearing in Chrysops, Tabanus, and 

 Hcematopota a shining spot or callus, the shape and coloration of 

 which afford useful specific characters. The males have an area in 

 the upper portion of the eyes, varying in extent according to the 

 species, composed of larger facets than those below ; this difference 

 is as a rule well-marked in the Tabaninae, but is often less conspicuous 

 in species of Pangonia or Chrysops. In the living insects the eyes 

 of the majority of Tabanidae are singularly beautiful, being often 

 golden-green, coppery-green, blue, or brilliantly metallic iridescent, 

 marked with purple or brown bands or spots ; these eye-markings 

 are of value for the identification of species, and are especially 

 brilliant in the case of females of Chrysops and Hcematopota, which, 

 as remarked by Girschner,f " possess probably the finest eyes of 

 all insects." After death, however, the colour of the eyes rapidly 

 changes to a dull brown or brownish-black, until little or no trace 

 of the markings remains. J 



In all Tabanidse the three-jointed antennae, which in the genus 

 Chrysops attain a considerable length, project conspicuously in 

 front of the head. In Tabanus and Hcematopota the proboscis 

 (labium), which contains the piercing mouth-parts, is soft and fleshy, 

 of moderate length, terminated by a pair of large and conspicuous 

 labella, and depends vertically beneath the head. In Chrysops 

 the proboscis, which is still vertical, is more slender and often 

 distinctly elongate ; while in Pangonia (sens, lat.) it is strongly 

 chitinised, generally slender, and often horizontal in position and 

 remarkably long, sometimes even considerably exceeding the body 

 in length. The palpi, one of which can be seen on each side of the 

 base of the proboscis, are two-jointed ; the terminal joint, which 

 differs in shape in the two sexes, is usually swollen and fleshy in the 



* In certain species of Chrysopa, e.g., Ch. longicornis, Macq., and Ch. fusca, 

 Ricardo, the eyes are narrowly separated above in the male. 



| Of. E. Girschner, Berliner Entomologische Zeitschrift, Bd. XXXI., p. 156 (1887). 



J In the figures illustrating this work the eyes are shown as seen in dried 

 specimens, from which the drawings had necessarily to be prepared. 



