BY FREDERICK A. A. SKUSE. 311 



Veins. 



Costa (v. costalis). A, h. 



Transverse shoulder- vein (v. trans, humeralisj. x. 



Auxiliary (v. auxiliaris). a, s. 



First longitudinal (v. long. Ima). a, B. 



Marginal cross-vein (V' trans, marginalis). x x. 



Second longitudinal (v. long. 2da), b, C. 



Third longitudinal (v. long. 3a). b, D. 



Middle cross- vein (v. trans, media), x x x. 



Fourth longitudinal (v. long. 4a). c, d, e. 



Posterior cross-vein (v. trans, posterior), x x x x. 



Fifth longitudinal (v. long. 5a). c, f, g. 



Ohs. — Following the plan adopted by Winnertz in his treatment of the 

 species of Geratopogon (Linn. Entom. VI. p. 13), I have by means of micro- 

 metrical measurements divided the wings in tiie species of all the genera 

 into one hundred parts, thereby being enabled to tabulate the respective 

 positions of the tips of the first, second, and third longitudinal veins between 

 the base and apex of the wing. In the plates I have represented all the 

 wings on the same scale of one hundred divisions, which will be found more 

 useful than if the relative size of the winces had been retained. 



