288 



THE WINGS OF APHIDIDM 



The media. — The data upon which the identification of media is based 

 is given above. As to the nature of this vein, it may be three branched, as 



Fig. 293. — The tracheation of the fore wing of Chermes 

 abietis (After Patch). 



in Aphis (Fig. 290), or two-branched, as in Shizoneura (Fig. 292), or it may 

 be reduced to an unbranched condition, as in Chermes (Fig. 295). 



The cubitus. — "Cubits is present in 

 all genera of Aphididae and in all of 

 them unbranched." 



The anal veins. — A single anal vein 

 is developed in this family. That this 

 is the first anal vein was demonstrated 

 by the finding of the second and third 

 anal tracheae in wings of newly emerged 

 aphids (Fig. 290); but veins are not 

 developed about these tracheae. 



Fig. 294. — The tracheation of a hind 



wing of a nymph of Chermes pini- 



folicB (After Patch). 



.Sc+jR+^f+Ct/ ^'«'^^ gc 



Fig. 295. — The venation of the wings of Chermes (After Patch). 



