168 



VETEEINAEY HYGIENE 



Fig. 33.— Ear Cockle, showing 

 the nematoid worms (Smith). 



live on it after it has been saved ; the latter are by far the 

 larger class. 



Ear cockle, Purples or Peiypercorn, is a disease of the ear 

 of wheat, oats, and rye, due to a nematode worm. Vibrio 



tritici (Fig. 33), which enters the 

 grain and converts it into a gall. 

 Externally the gall is dark in 

 colour, while its interior is filled 

 with a cottony mass consisting of 

 coiled up parasites. 



The animal parasites attacking 

 food after the life of the plant, 

 were especially studied by Megnin, 

 to whose researches, noticed in 

 : Magne's work, we are greatly 

 indebted. 



Two kinds of parasite attack forage and grain, viz., 

 insects and arachnidans. To the former belong Tcnehrio 

 mollitor (Fig. 34) which infects forage, and T. farina which 

 attacks grain. The latter is more serious than the former, 

 for the larvee of the Tenebrio of grain live in the flour, 

 whereas those of hay do not live in forage. In both cases 



they are very destruc- 

 tive and reduce the food 

 to powder. They are 

 actively assisted by Bos- 

 trichiis longus, B. spero- 

 cephalus, and Ptiniis fur 

 (Fig. 35) ; the larvae of 

 all these develop in the 

 food, and are conse- 

 quently most destruc- 

 tive. 



The Acari which live 

 on grain and forage belong to the genera Oribata, Gamasus, 

 Tyroglyplms, Cheyletus, Trombidium, and Argas. All these 

 are most destructive, while the Gamasus (Fig. 36) and two 

 species of Argas (Figs. 37, 38) cause such irritation to the 



Jig. 34.— Tenebrio 

 mollitor, slightly 

 magnified (Magne 

 and Baillet). 



Fig. 35.— Ptinus fur, 

 magnified (Magne 

 and Baillet). 



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