162 LEAF-MINING INSECTS 



The larva, from a study of the mines, appears to burrow towards 

 the end of the leaf first. Should it arrive at the end of the leaf 

 (and it almost invariably does), before attaining full growth, it 

 reverses its position and mines towards the base. The hole of 

 entrance and of future exit is apparently in all cases enlarged and 

 the excrement pushed through, as there is but little frass to be 

 discovered in the mine, while it can always be found in a greater 

 or less quantity at the opening or on the leaves below. No in- 

 stance has been observed in which one larva has injured more than 

 a single leaf of P. rigida, but a specimen of this insect was found 

 in Virginia upon the common scrub-pine (P. inops), the leaves of 

 which are shorter and more slender than those of the pitch-pine, 

 and, from observations made upon it, it would seem that one leaf, 

 if small, does not afford all of the food needed by a larva. 



Upon reaching full growth the larva spins a slight covering to 

 the mouth of the mine and retreats a short distance above it 

 (from 10 to 15 mm.). There, after spinning a few supporting 

 lines of silk, it transforms to a long and slender chrysalis, light- 

 brown at first but afterwards nearly black. When removed from 

 the mine the pupa is very active, jerking the short end of the 

 abdomen (which extends below the wing cases) from side to side 

 with rapidity. The duration of the pupa state is from ten to 

 fourteen days. The moth makes its exit from the pupa shell 

 without disturbing the position of the latter, leaving it attached 

 by its threads some distance up the mine, and works its own way 

 to the entrance. 



There are certainly two broods of this insect each year, probably 

 three, and possibly more in exceptional seasons. 



Aristotelia 



The three native species of this genus of which published 

 accounts are available are so different in habits that we 

 cannot generalize, but can only quote the brief notes on 

 one of them. 



Concerning A. physaliella, Clemens (1872) stated: 



The larva mines the leaves of the "Ground Cherry (Physalis 

 vicosa) in September, and perhaps earlier, as I found then many 



