Notes on North American Species of Nepticitla. 



101 



Mine of 



TV. argentifasciella. 



Described from twenty-four specimens bred from mines on 

 leaves of basswood, TWia americana L., at Cincinnati. I have 

 also two captured specimens. The ^gg is deposited on the 

 upper surface of the leaf, but the larva upon 

 hatching mines much closer to the lowxr than 

 to the upper epidermis, forming at first a very 

 narrow serpentine mine about 3.5 to -t cm. 

 in length, with a width nowhere greater than 

 .5 mm. This portion of the mine is scarcely 

 visible from the upper side, except for the 

 tiny specks of leaf substance consumed here and there. \\'ith- 

 in the last 24 or 36 hours of larval life the linear mine sud- 

 denly expands into a blotch or broad tract, 3.5-4: mm. in 

 breadth. In this area, which often obliterates part of the early 

 serpentine mine, the parenchyma is almost entirely consumed, 

 leaving the mine semitransparent and pale green. The larva 

 spins a somewhat flattened reddish cocoon, broader at its an- 

 terior end. 



Types in my collection. 



This species can not be confounded with any of the de- 

 scribed species. The silver markings are more brilliantly 

 lustrous than in any other species I have seen. 



21 



