124 GRAMMAR OF ENTOMOLOGY. 



edge or just below it, is called the costal nervure 

 (nervura costalis} ; and the portion of membrane, 

 if any, above this nervure, is the costal cell, or if 

 divided by minor nervures, the costal cells (cellulce 

 costales). 



448. The incrassated portion of this nervure, 

 which is frequently observable at about two-thirds 

 of the distance from the body, towards the apex 

 of the wing, is called the stigma (stigma). 



449. The cells immediately beyond the stigma, 

 towards the extreme point of the wing, are called 

 the marginal cells (cellules marginales) ; these are 

 generally two or three in number ; and the cells 

 immediately below these, the submarginal cells 

 (cellulce submarginales). 



450. The wings of all insects present a some- 

 what triangular figure. The upper portion of this 

 triangle is called the costal region (regio costalis) ; 

 the outer portion, the exterior region (regio exte- 

 rior) ; the lower portion, the inferior region (regio 

 inferior) ; and the central portion, the central 

 region or disk (discus). Attention to this will 

 render most descriptions of the numerous cells and 

 nervures intelligible. 



451. The legs of insects do not undergo the 

 same degree of variation as the wings ; they are 

 of a more uniform structure, not only as regards 

 different kinds of insects, but as regards the legs of 

 the same insects : they are six in number, or three 

 pairs, the fore legs (propedes), which are the 



