164 



INSECT TRANSFORMATION 



animal. 1 The wings of Hippobosca, though of a normal 

 length are narrow and feeble in texture for an insect of such 

 bulk. Allied flies (Lipoptera) that attack deer, are observed 

 usually to cast or tear off their wings after resting on the 

 skins of the beasts on which they feed ; here, therefore, we 

 notice an artificial loss ol wings in the life-time of each 

 insect. Other members of the same family that infest the 

 nests of birds and feed on their blood (such as Stenopteryx) 

 have the wings so abbreviated or so narrow as to be useless for 



FIG. 93. 



a, Sheep-ked (Melophagus ovinus). x8. 6, Puparium of 

 Ornithomyia (side view) (t, transverse suture ; I, lateral suture) ; 

 c, the same, dorsal view with fly emerging, x 8. | 



flight. It is not surprising to find that some allied genera 

 are entirely wingless, for example the keds (Melophagus, Fig. 

 93 a) which frequently infest sheep, being found in numbers 

 clinging to their wool. 



These curious parasitic Diptera, which show in their various 

 groups the degeneration or the total disappearance of wings, 

 have all a very remarkable life-history. The egg is hatched 



1 E. A. Ormerod : " Report of Observations of Injurious Insects ". 

 London, 1895, 1898. 



