1917] Pupal Wings of Nepticula 239 



Cubitus. — The cubital trachea is unbranched, and in the 

 earlier pupa extends nearly to the wing margin. 



Anal Veins. — At least one anal vein is present preceded by a 

 trachea which often persists in the imago. In some species 

 and genera, a second short anal vein is present, but no trachea 

 persists. 



The question of homology of wing veins among forms with 

 degraded venation, as is often the case in the Microlepidoptera, 

 sometimes presents a puzzHng problem, which in many cases 

 can only be solved by a study of pupal wings; involving as has 

 been hinted in the above presentation of the pupal wings of 

 Nepticula, a study of the more generalized as well as the most 

 specialized wings within the group, since the tracheae show the 

 same tendency toward reduction in number of branches as is 

 seen in the wing veins of the imago. 



EXPLANATION OF PLATE XVIIL 



Fig. L Pupal fore wing of Nepticula platanella a few days before emergence. 

 Fig. 2. Pupal fore wing of N. platanella at an earlier stage than that represented 



by Fig. L 

 Fig. 3. Pupal fore wing of Nepticula rosaefoliella. 



Fig. 4. Pupal hind wing of N. platanella of the same age as the fore wing in Fig. 2. 

 Fig. 5. Hind wing of N. platanella just after emergence. 



