360 



UTILITARIAN ZOOLOGY 



INJURIOUS SPIDER- LIKE ANIMALS (ARACHNIDA). The only 

 forms of great importance here are the Mites (Acarina). Mange- 

 and Itch-Mites, injurious to domesticated animals, have already 

 been mentioned (see p. 196). Poultry are attacked as well as 

 quadrupeds. Fowls are also liable to be infested by Red Fowl- 

 Mites (Dermanyssus gallince), which suck their blood and set up 

 an intolerable itching. 



Domesticated animals are also often attacked by Ticks 

 (Ixodid&)i which are able to draw large quantities of blood, and, 

 what is more serious, may convey the germs of disease. Infec- 



tion by means of one such 

 Tick (Ixodes reduvius) is, 

 for example, the cause of 

 4< louping ill " in sheep. 



Cultivated plants also 

 suffer from the attacks of 

 Mites, among which the 

 following may be men- 

 tioned : Currant Gall - 

 Mite (Phyt optus ribis], 

 Red Hop --Spider" (Te- 

 tranychus telarius], Red 

 Plum-" Spider " (T. ru- 

 bescens], and Harvest or 

 Gooseberry - " Bug " ( T. 

 autumnalis}. 



Other kinds of Mite 



SDOil fumitUrC and attack 

 food 



Big. 1257. Stages m Life -History of Liver -Muke (Fasciola 

 hepatica), enlarged. A, ciliated larva; B, sporocyst, within which 

 rediae are developing; c, redia, within which a new generation of 

 redise is developing; D, redia, with contained cercarise (G, opening 

 by which these escape; D, intestine); E, cercaria. B to E are 

 parasitic within the water-snail F (Limncea truncatula), from which COCCSC and SUP~ar. 

 E escapes to encyst on the stem of a plant. 



INJURIOUS MYRIAPODS 



(MYRIAPODA). Some of the Millipedes ("false wire-worms") 

 attack the underground parts of various plants, or may damage 

 soft fruits. 



INJURIOUS FLAT- WORMS (PLATYHELMIA). A large number of 

 Flukes (Trematoda) and Tape-Worms (Cestoda) are parasitic 

 within the bodies of domestic animals, as previously stated in 

 dealing with the personal enemies of man (see p. 342). A few 

 details may be appropriately added. 



Flukes (Trematoda). It is only necessary here to refer to the 



