INSECTS PARASITA DIAGRAM 7. 145 



gastric juice, and therefore the larva does not die. It attaches 

 itself to the surface of the stomach, and continues to live there 

 until the time for its first metamorphosis, then it drops into the 

 food, and is expelled from the body, when it becomes a fly at the 

 end of a certain time. 



The Gadfly, instead of having a proboscis like the flies, has a 

 sucker like the gnats. It pierces horses to feed on their blood, 

 making a large wound, from which the blood flows in abundance. 

 The gadfly also attacks man ; its puncture is not dangerous, but it 

 may communicate either to animals or to man a serious disease 

 called carbuncle. This disease 

 generally shows itself by a bright 

 red patch, in the middle of which 

 is a black spot. Where it is sup- 

 posed to exist, a doctor should im- 

 mediately be consulted. Gadflies 

 and other insects which similarly 

 pierce the skin may thus convey 

 carbuncle, but the disease may also 

 be contracted by touching the fresh Gadfly, 



skins of animals which have it. The flies themselves only convey 

 it when they have previously rested on animals which have 

 carbuncle, or have died of it. 



ORDER PARASITA. 



All those animals are called parasites which live on or in other 

 animals. There are also parasitical plants. All parasitic animals, 

 do not belong to the class of insects, although some do. The 

 cestri of which we were speaking, which grow either under the 

 skin of cattle or in the stomach of horses, are parasites, but only 

 in the larva state. In the insects of the order of which we now 

 speak, some are parasites during all their life as the louse ; and 



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