INSECTS DIPTEHA DIAGHAM 7. 



145 



a serious disease called carbuncle. 

 It generally begins by a very bright 

 red patch, in the middle of which 

 is a black spot. When this disease 

 is supposed to exist, the doctor 

 should immediately be consulted. 

 Gradflies and other insects which 

 similarly pierce the skin may thus 

 convey carbuncle, but it may also 

 Gadfly. "be contracted by touching the fresh 



skins of animals which have it. The flies themselves only con- 

 vey it when they have previously rested on animals which have 

 carbuncle, or have died of this disease. 



OEDEE PAEASITA. 



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 stomachs 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 j 

 and others are so only in the adult state, like the flea. None 

 of them have wings. 



The flea has a sucker, with which it makes painful punctures, 

 like the bug and the gnat. In the larva state, they are very 

 active maggots, but these larvse do not live on man ; they live in 

 straw, dust, and old furniture. 



The louse attaches its eggs, or nits to the hair ; they have a 

 small lid which the larva raises to emerge^ from it. It already 



