316 



THE WINGS OF TRICHOPTERA 



become invisible before the medial fork is reached. The cubital and first 

 anal tracheae coalesce for a short distance at the base of the wing and then 

 separate; the cubital trachea divides into two a short distance before the 



Fig. 326. — Base of the fore wing of Mneinonka. 

 point where vein Cu separates from the first anal vein and both branches 

 follow the Z-shaped course of this vein. There is no trachea in the pos- 



r«+ 



Fig. 327. — Base of hind wing of Mnemonica. 

 terior arculus. The first anal trachea I am unable to trace beyond the 

 point where vein Cu branches off, owing to the atrophied condition of the 

 first anal vein. The second anal trachea is clearly visible. 



