314 APPLIED ENTOMOLOGY 



for the Hessian Fly to lay its eggs on before the main planting is avail- 

 able. This will produce an abundance of the insects to attack the crop 

 the following spring. All such plants should be destroyed before the 

 maggots in them have reached the flax-seed stage. 



The use of good seed, planted in soil that has been thoroughly culti- 

 vated to break up all the lumps of dirt and thus provide a compact, 

 fine soil, is very helpful, and the addition of plenty of fertilizer is also of 

 importance. 



One writer has summarized control methods for the Hessian Fly 

 as follows: "Sow the best of seed in thoroughly prepared, fertile soil 

 after the major portion of the fall brood has . . . passed out of existence, 

 and, if possible, sow on ground not devoted to wheat the preceding year. 

 In the spring-wheat section late seeding will not apply. It seems likely, 

 on the contrary, that the earlier it is sown in spring the less it will' suffer 

 from the Hessian Fly, " (Webster). 



Another Itonidid attacking wheat, and also barley, rye and oats occasionally 

 is the Wheat Midge {Contarinia tritici Kirby), a native of Europe, first noticed 

 near Quebec about 1819, and which has now spread over the wheat-growing 

 regions of the East, and through the Mississippi Valley. The adults are very 

 small, yellow or orange colored, and appear in June. They lay their eggs in the 

 chaff covering the growing kernels of grain, and the reddish maggots suck the 

 juice from the kernels causing them to shrivel, blighting the heads. When full- 

 grown, the maggots pupate in the ground, usually passing the winter in this stage. 

 There is generally only one generation each year. 



For many years, this was a very serious enemy of wheat, the loss in New York 

 being estimated at $15,000,000 in 1854, but since about 1860 it has been less 

 destructive and only local in its attacks. Plowing infested land deeply in the fall 

 so that the insects wintering there will be buried too deeply for them to escape 

 the following spring: burning the chaff and screenings after threshing the grain 

 from infested fields, and rotation of crops are the control methods used for 

 this pest. 



Family Tabanidae (The Horse Flies or Gad Flies). — Those pests of 

 cattle, horses, and occasionally of man also (Figs. 330 and 331) are in many 

 cases quite large insects, with bodies an inch long though most of them 

 average a third to half an inch in length. The head of the adult is large 

 and fits onto the thorax somewhat like a cap. Only the females feed 

 on blood, the males lacking some of the mouth parts necessary with 

 which to pierce the skin. They therefore feed on such plant juices as 

 they may be able to obtain, honey dew and other similar materials. 



The eggs are laid in masses on plants over water or marshes, and the 

 larvae live in water, damp places, or in the earth when it is soft, and are 

 carnivorous, feeding on snails, small insect larvae, etc. 



The family is a large one, both in this country and elsewhere. The 

 larger species, (one has a black body and smoky wings), are often noticed 



