54 



ENTOMOLOGICAL NEWS. 



[March, 



times very close to the costal, but rarely extending much beyond 

 the middle of the wing. This vein gives off, normally, six 

 branches, which are called the subcostal venules. Of these, one 

 or two usually separate from the main trunk before the end, and 

 the others are grouped at the tip. Sometimes, to facilitate this 

 grouping, a cell is formed around which the branches start, and 

 this, when present, is termed the accessory cell, marked a in the 

 figure. Sometimes, instead of all the branches reaching either 

 the vein or the accessory cell, a stalk may be sent out, which in 

 turn branches. So in the figure, branches 8 and 9 are from a 

 stalk out of the tip of the accessory cell; 6, 7 and 10 are out of 

 the accessory cell, while 1 1 is out of the subcostal itself. The 

 accessory cell is present in comparatively few families only, and 

 its presence or absence is of systematic value. The arrangement 

 of the subcostal venules is also used in classification, and quite 

 frequently some of them are wanting. 



Below the subcostal at base is the median vein running parallel 

 to, but more or less diverging from the subcostal, and extending 



usually about as far into the wing. The space between the sub- 

 costal and median veins is called the median cell. Quite usually 

 a slender transverse veinlet extends from the tip of one to the tip 



