1114 



PRACTICE OF AGRICULTURE. 



p.v:iT in. 



convsx and thick ; the wing* l*o> instead of belnj? folded orer drop of froth of its o\Tn makinfr, and is then commonly kno-wn 

 each other, are deflexed, and embraL-e the sides of the bmly. as the cuckoo-spit insect; bv tec-dinf; upon the sap it causes the 

 Thereare,comparalively, few homopterousinsectsin England; leaves to curl up, and the growth of young plants is thus naa- 

 but the frog-hoi)per (Cichda spumaria L.) is a good example terially checked, 

 when in its perfect or winged state. The larva resides in a 



7654. The different orders of insects we have now enumerated are connected by others of an inferior 

 extent, and which are called osculant orders. But as a description of these is not essential to our present 

 purpose, and as they do not contain any decidedly injurious insects, we shall merely refer the reader to 

 the Hbree Entomologicae of Macleay, and the Entomology of Messrs. Kirby and Spence. 



SuBSECT. 3. Insects injurious to live Stock. 



7655. All organised beings, whether animal or vegetable, are subject to be attacked and destroyed by 

 insects. Even man himself is not exempt from the dominion of these small but formidable creatures. 

 For some wise but unknown purpose, there are peculiar species appropriated to receive their nourishment 

 from man alone, and which cannot exist in any other situation. The remedies for these must be pre. 

 scribed by the physician; but it is the business of the intelligent agriculturist to make himself acquainted 

 with sucli as are injurious or hurtful to the animals and plants, upon which, the success of his operations 

 mainly depends : for there are as yet no agricultural physicians, to whom the farmer can apply for advice 

 or information when his labours are counteracted by insect devastators. We shall therefore briefly notice 

 the domesticated animals and cultivated plants most subject to these injuries, pointing out the most 

 efficient modes by which they may be checked. 



7656. The hotse. Tlie principal foes to this noble animal are the horse-bee [CE'stius fequi) and gad-fly 

 {CE. hajmorrhoid^lis). The first deposits its eggs on such parts of the body as are liable to be licked by 

 the tongue ; and the animal, unconscious of what it is doing, thus conveys its enemy into its stomach ; the 

 young larvae are there nourished, and become whitish rough maggots {Jig. 969. c), which are known by 



the name of bots. They attain their full size about the latter end of May, and are voided by the anus 

 from that time until the end of June. On dropping to the ground, they find out some convenient retreat, 

 where they change into a chrysalis ; and in six or seven weeks the fly appears. The female {b) is distin- 

 guished from the male () by the lengthened shape of her body. The inside of the knee is chiefly selected 

 for depositing her eggs, which will frequently amount to four or five hundred on one horse. The other 

 species {(E. haemorrhoidalis L.) is still more troublesome ; it deposits its eggs upon the lips, and causes ex- 

 cessive and distressing uneasiness to the animal. Mr. Bracy Clark, who has investigated the history of 

 these insects with great ability, observes that in ordinary cases it is not improbable that they are beneficial 

 to our cattle, by acting as perpetual stimuli or blisters ; yet, when they exceed certain limits, they produce 

 disease, and sometimes death. (Clark in Linn. Trans, vol. iii.) The prevention of bots belongs to tlie 

 farmer, the cure to the veterinary surgeon. The first may be effected by watching the animal at the 

 season when the female deposits her eggs (usually in August and September), and should the horse ap- 

 pear much agitated in its pasture, there will be good reason to suspect it has been attacked by the fly ; the 

 eggs may then be removed by the brush and currycomb, or by a pair of scissors. When the disease is 

 certain, one of the best methods to destroy the insect is to fasten a bag net on the horse, for the purpose 

 of catching the excrement, as well as the full-fed larvas. By throwing the dung every morning into a deep 

 pit, any larvae that may be enclosed in it will thus be prevented from working their way to the surface 

 when their last transformation is about to take place, and their death will cut off a numerous progeny. 

 There are other dipterous insects which feed upon the blood both of horses and cattle ; the most formi- 

 dable of these are the horse-flies (TabJini, Ic, I) ; others, much smaller (Stom6xys calcitrans), assail him in 

 every situation during summer, and dart their long probosces into his legs and belly. But none are more 

 trying to him than the forest fly (Hippob6sca equina L.), which runs sideways or backwards like a crab, 

 and shelters itself in those parts least covered by hair : it may, however, be caught by the hand, when the 

 animal is in his stall ; but its substance is so hard, that it can only be destroyed by rolling it between the 

 finger and thumb. 



7657. Hoi-ned cattle are likewise subject to the attacks of a peculiar species of gad-fly {CE. bbvis, d, c, /), 

 which causes them great terror and distress. The larva (e) is smooth and fat : and the chrysalis (/) 

 opens by a lid (m) when the insect (d) emerges from it. The herdsman may know when this insect ap- 

 pears among his flocks, by the agitation they exhibit ; the whole herd, with their tails erect, or carried 

 in some grotesque attitude, gallop about and utter loud lowings. When oxen are employed in agricul- 

 ture, the attack of this fly is often attended with danger, as they become quite unmanageable, and, whe- 

 ther in harness or yoked to the plough, will run directly forward. Their harness at this season should 

 therefore be so constructed as to be easily loosened. The eggs are deposited within the skin of the animal, 

 and in a wound made by a tube resembling an auger, with which the female is provided. These flies 

 only attack young and healthy subjects ; but, independently of the terror they create, do not appear to 

 occasion any material injury. The cattle of Hungary and the neighbouring countries, as also those 

 of Abyssinia, are subject to more deadly enemies, which fortunately are unknown in England. 



7658. Shtep are also infested by another species of gad-fly (ffi. ovis L., e, h, i), which deposits its 

 eggs in the inner margin of their nostrils. The moment the fly touches this part of the sheep, they 

 shake their heads, and strike the ground violently with their fore feet ; at the same time, holding their 

 noses close to the earth, they run away looking about them on every side, to see if the fly pursues : they 

 will sometimes crowd together in a rut or dusty road with their noses close to the ground. The larva; (/) 

 are white, flat on one side and convex on the other ; they inhabit the cavities of the maxillary sinuses, 

 and crawl, when the animal is dead, into those of the horns and frontal sinuses; when full grown, they 



