8 CROP PEST COMMISSION OF 



a whole year, and sometimes more ; and as even an approach to 

 the conditions of the natural habitat and food of the larva is 

 difficult to attain and perpetuate for any length of time by 

 artificial means, the rearing of the various species under ob- 

 servation can riot be otherwise than a very tedious undertaking. 



Various common names, such as horseflies, gadflies, deer- 

 flies, dogflies, earflies and woodflies,* are applied to these in- 

 sects in different sections of the country. They belong to a single 

 family called Tabanidae, and all of them are of medium to 

 large size, with wings either transparent or clouded, or spotted 

 with black or brown. 



They are of especial interest to the economic entomologist, 

 the farmer and the stock raiser on account of their blood-suck- 

 ing propensities and the injury and annoyance they cause to 

 domesticated animals on account of this habit. Not only are 

 horses attacked, but cattle, hogs and sheep as well, although the 

 latter are more or less protected by their wool, which to some 

 extent acts as a blanket over most of their bodies. 



All through the group the males and females are easily 

 distinguished from one another by the eyes, which in the male 

 sex are united on the front of the head, while in the female sex 

 there is a rather narrow space on the front of the head sepa- 

 rating the eyes from one another. It is worth while to be able 

 to tell the sexes apart, for, like the mosquitoes, it is only the 

 females that suck blood, or, in other words, that are trouble- 

 some to stock. The males, and, under certain circumstances, 

 the females also, live on the nectar of flowers or the juices of 

 plants, or on other sweet liquid or semi-liquid substances. 



These flies are usually troublesome only when the sun is 

 shining, or at least after eight o'clock in the morning. They 

 rest on foliage or trunks of trees, on posts, stumps, fences or in 

 other inconspicuous places during the night and early morning 

 hours, and then come forth in myriads as soon as the sun warms 

 the atmosphere, to get a meal of blood from any animal that 

 comes in their way ; ad it seems that the hotter the sun the 

 more active they are, and the more injury and annoyance they 

 cause to farm animals. 



*Aeeordin{ to Mr. Harper Dean, Jr., the term "Mayflies" is applied in 

 parts of Virginia to certain species of Chrysops. 



