CHAPTER V 

 THE FLIES 



Family III. Tabanidae. — Diptera (p. 23). This family includes 

 the so-called horseflies or gadflies. The head and e3'es are large, the 

 latter often of a brilliant color. The third segment of the antennae has 

 four to eight rings. The proboscis of the female is adapted for piercing 

 the skin of animals. The males do not attack animals; their mouth 

 parts are less powerful than those of the females and are adapted for 

 feeding upon the juices of plants. The bod}- has fine hairs; there are no 

 bristles. The flight is strong and swift and is accompanied with a 

 tormenting buzzing noise. 



The eggs of Tabanidae are deposited in masses upon vegetation grow- 

 ing in wet marshy ground. The larvae are carnivorous and are aquatic 

 or live in moist earth. 



Tabaxus Atratus 



Tabanidae (p. 35). This is the common large black horsefly, having 

 a M'ide distribution in the United States. It is one of the larger species 

 of the family, measuring an inch or more m length and having a body so 

 uniformilv black as to attract attention even when it is upon the wing 

 (Fig. 20)." 



The eggs are deposited in masses, usually upon the stems of plants or 

 grasses growing in the vicinity of water. In about seven to ten days 

 there is hatched a large cylindrical larva which tapers to a point at both, 

 ends and has an integiunent that is somewhat transparent (Fig. 20, a). 

 At this stage it lives mostl}^ in moist earth into which it burrows actively, 

 feeding mainly upon worms and the larvae of other insects. While the 

 period of larval life is long, in some observed cases lasting several months 

 to a year, the stage of the pupa (Fig. 20, b) is short, the fly emerging from 

 its case after a few daj-s of pupation. It is probable that the broods are 

 carried over the winter in the larval stage. 



Effect. — The black horsefly is common throughout the summer 

 months, attacking cattle and horses usualh' in the open sunny pasture, 

 and inflicting with its long piercing mouth parts a painful wound. For- 

 tunately it does not attack in swarms as does the buffalo gnat, nor does 

 it instill with its bite as much poison. There is evidence of the severity 

 of its wound, however, in the drop of blood which wells up from the seat 

 of puncture after the insect has left its victim. While there is little 



