DIPTERA BRACHYCERA. 



747 



Fam. 17. Tabanidae. This family includes the Horse-flies or Gad-flies 

 sometimes termed Cleggs or Breeze-flies. They are stout, large flies, with a 

 fleshy proboscis bearing stylets capable in the female of piercing the skin. 

 Antennae projecting, with four segments. Eyes very large especially in 

 the male. Well developed squama. These are dangerous flies usually 

 found near inland water. The females suck the blood of horses, cattle and 

 man, and are said to transmit the bacillus of anthrax from one animal to 

 another. Members of the common British Tabanus attain a length of one 

 inch, and are conspicuous by their loud humming. The larvae are maggot- 

 like, live in damp earth and eat snails and insect grubs. Some 1,500 

 species are known. Pangonia. 



Fam. 18. Acanthomeridae. Antennae end in a 

 seven-segmented process with a terminal style. 

 Squama rudimentary. Proboscis short. Acantho- 

 mera and Rhaphiorhynchus are the two American 

 genera which compose this family. Some specimens 

 attain a length of two inches and are the largest 

 flies known. 



Fam. 19. There vidae. Smallish, slender flies with 

 a weak fleshy proboscis. Short three-segmented 

 antennae, pointed. Very slender legs. The larvae, 

 with nineteen segments, frequent decaying wood ; the 

 imago is said to prey on other insects. Thereva. 



Fam. 20. Scenopinidae. Small, black, active flies, 

 with three-jointed antennae. Proboscis not pro- 

 jecting. No empodium. A very small family of 

 flies mostly found on windows. The elongated 

 white larvae frequent carpets and woollen fabrics 

 and decayed wood, and are said to live on the larva 

 of the " carpet -moth." 



Fam. 21. Nemestrinidae. Medium sized, stout 

 flies with in some species a very long proboscis. 

 Short antennae of three joints with a jointed ter- 

 minal appendage. Wing nervures very complex for a 

 fly. The long proboscis sucks nectar from flowers. 

 The larva of Hirmoneura is parasitic on that of a 

 Lamellicorn beetle (RMzotrogus) which feeds on turf, 

 although the egg is laid in the burrows of some 

 wood borer, from which the larva emerges and 

 migrates by the aid of the wind. 



Fam. 22. Bombyliidae. Bee-like flies of stout 

 build, hairy. The three- jointed antennae end as a 

 pointed process. Proboscis often long. Mandibles 

 and first maxillae piercing. Weak legs and many- 

 celled wings. Bombylius poises in the air almost motionless and then 

 darts away with almost invisible rapidity. It haunts the sunny spots of 

 woods and glades and sucks the nectar of flowers. The larvae of some Bom- 

 byliidae make their way into the nests of certain Mason -bees and, after 

 gently absorbing the juices of the pupae of their hosts, pupate. The pupa 

 is capable of breaking down the masonry of its prison. The larvae of 

 other species render a public service by feeding on the eggs of locusts. 

 The family is large and widely . distributed. 



Fam. 23. Acroceridae. Flies of medium size, with small head bent 



FIG. 478. Pangonia 

 longirostris. x 1. Nepal 

 (after Hardwicke). 



