58 



ORGANS OF THE DIPTERA. 



direct your attention ; but I find it impossible to con- 

 vey to you, without the aid of magnified drawings, 



A, Antenna of the Tipulida — b, of Tabanus — c, of Miuca. 



a precise idea of the variations in structure which 

 they exhibit. They have, however, one common 

 character ; they are formed for imbibing food by 

 suction ; of this the common fly is perhaps the most 

 familiar example. In other genera, as in that to 

 which the " small grey-coated gnat " belongs, the 

 labrum, mandibulse, maxillae, and lingua, become 

 converted into a series of sharp and delicate instru- 

 ments, which not only pierce the skin, but form a 

 tube for the passage of the blood on which they live. 



A, Mouth of Tabanus— B, of Miisca. 



