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TEXTBOOK OF ZOOLOGY 



Many of the most useful insects are found in this order. The rob- 

 ber flies, Asilidae; the syrphids, Syrphidae; the bee flies, Bombyli- 

 idae; and the taehinids, Tachinidae, contain many species that are 

 valuable to mankind. On the other hand, the mosquitoes, Culicidae ; 



Fig. 194. — Adult female sheep tick, Me.lophaous ovinus L,inn. (From Knowlton, 

 Rowe, and Madsen, by permission of the Utah Agricultural Experiment Station.) 



Fig. 195.— Life history of the housefly, Musca domestica L. A. A, adult; B, ma- 

 ture larva; C, pupa inside puparium ; D, eggs. (From Knowlton, Rowe, and 

 Madsen, by permission of the Utah Agricultural Experiment Station.) 



the fruit flies, Trypetidae; the houseflies, Muscidae; the botflies, 

 Oestridae; and the sheep tick, Hippoboscidae, damage food and 

 spread disease and suffering. The larvae of some families are called 

 maggots. Some larvae are parasitic, others predacious, or seaven- 



