ORDER DIPTERA. 133 



through a T-shaped opening, or rarely through a transverse 

 rent between the seventh and eighth abdominal segments. 

 The following families, to and including the Xylbphagidae, 

 belong to Section 1, Brachycera, in which the antennce 

 are short and 3-jointed: 



Family Lonchopteridae. Wings with the three basal cells of moder- 

 ate size, and of nearly equal length; antennae with an apical bristle. 

 Lonchoptera ripnria Meig. 



Family Dolichopodidae. First basal cell rather short, the second 

 united with the discal cell, the third small; auxiliary vein running 

 into the first longitudinal vein; third longitudinal vein simple, the 

 fourth sometimes furcate; no intercalary vein. Hypopygium sym- 

 metrical, bent under the abdomen; empodium small, membrana- 

 ceous, linear. Generally metallic green, brisk, small, restless flies 

 which devour other insects. Dolichopus cuprinus Wied. 



Family Empidse. Body rather long; head rounded, the eyes in 

 the males touching each other above; third joint of antennae simple, 

 with a terminal style, or a terminal or dorsal bristle. These flies are 

 voracious, attacking other flies. Empis armipes Loew. 



Family Cyrtidae. Head often minute, the eyes very large and 

 meeting above; thorax and abdomen much inflated; tegulae vaulted, 

 very large; proboscis often very long. Certain of the larvae are para- 

 sitic in spiders or their cocoons. Acrocera Mmaculata Loew; Lasia 

 klettii O. Sackeu. 



Family Scenopinidse. Three basal cells very large; third joint of 

 the short antennae without style or bristle. Larva very long and 

 slender; occurring under carpets, and probably feeding on carpet- 

 moths and Psocids. 



Family Therevidse. Differing from Asilidae in the labella being 

 not horny, but fleshy; antennae short, with a terminal style of varia- 

 ble form, sometimes wanting. Larvte like those of Scenopiuus, 

 with the segments in most of them constricted, the body appearing 

 as if composed of nineteen segments behind the head. Thereva al- 

 biceps Loew. 



Family Bombylidse. Three basal cells of the wing much pro- 

 longed, with usually four posterior cells, and the third joint of the 

 antennae not ringed; the proboscis is long, and the body is in most 

 of the species densely hairy. They are mostly very swift on the 

 wing, often hovering motionless in the air, and then darting away 

 as quick as a flash. The larvae of Bombylius are parasitic on bees; 

 those of Systffichus areas O. Sacken and Aphcebantws mus O. Sacken 

 feeding on the eggs of locusts (Canmula and Caloptenus). 



Family Nemestrinidse. Many have wings with numerous cross- 

 veins, so as to be almost net-veined. In the African Megixt&rhyncJms 

 longirostris, a fly only about two-thirds of an inch in length, the 

 proboscis, which it uses to suck the nectar from the flower of 

 Gladioli, etc., is nearly three inches long. The European Hirmo- 

 neura obscura deposits her eggs within the burrows of Anthaxia, a 

 Buprestid beetle; the freshly hatched larva differing very singularly 

 from older larvae, the sixth to twelfth segments being each provided 

 with a pair of hooks, and they are supposed to attach themselves to 



