DIPTERA. 



361 



M. Marey has determined that a common fly when held cap- 

 tive moves its wings 330 times a second ; a honey bee 190 

 times, and a cabbage butterfly (Pieris) nine times. The wings 

 describe a figure 8 in the air. (Cosmos.) Landois, calcu- 

 lating the rapidity of the vibrations by the sound produced 



anterior of the small basal cells ; M, third basal cell, or posterior of the small 

 basal cells; JV, anal or axillary corner of the wing; O, alar appendage, (alula). 



FIG. 271 (2). Wing of Empis. t, anterior branch of the third longitudinal vein; 

 u, anterior intercalary. 



Fig. 271. 



FIG. 271 (3). Wing of Dasypogon. t,. anterior branch of the third longitudinal 

 vein; u, anterior intercalary vein; v, posterior intercalary vein. From Loew. 



Comparing the wing of Ortalis with that of tine bee and butterfly figured on 

 page 23, we should prefer to use the same terminology and call I, m, n, the margi- 

 nal vein ; A, 6, the costal ; c, d and e the three branches of the subcostal vein ; /, the 

 median vein ; h, the submedian ; and r, the internal vein. In Macquart's system, 

 modified slightly by Sacken (fig. 270), b, I, is the costal; cm, the subcostal; d and e, 

 the median ; /, the submedian, and g the internal vein. 



