structs oval mines in the leaves of aspen. It is occasionally quite 
abundant in the Lake States and Maine. L. corylisella Chamb. 
mines the leaves of hazel in Maine. 
Marmara fasciella Chamb. is widely distributed, probably oc- 
curring throughout the range of its host, white pine. Eggs are 
laid on the bark of branches of the host. Young larvae bore 
through the bark and construct linear mines in the inner bark. 
Winter is spent as a larva in the mine; pupation occurs during 
late spring, and adults begin to appear in late May. Several other 
species of Marmara have been recorded mining the inner bark 
‘of twigs of balsam fir, oak, willow, and other trees (258). 
Phyllocnistis populiella Chamb., the aspen leaf miner, is widely 
distributed in southern Canada and the Northern States. It feeds 
on various species of poplar, especially trembling aspen. In the 
Eastern States, it has been recorded as far south as West Vir- 
ginia. Eggs are laid near the tips of young leaves in the spring. 
The larvae form tortuous mines in the leaves (fig. 163), mostly 
on one side of the midrib (154). Noticeable infestations have been 
observed in Maine. 
Phyllocnistis liriodendrella Clem. larvae mine the undersides of 
young leaves of yellow poplar and P. magnoliella Chamb., the 
undersides of young leaves of magnolia. The mines originate near 
the outer margins of the leaves and continue tortuously until large 
portions of the upper surfaces are detached. The damaged areas 
have a bluish cast. P. liquidambarisella Chamb. mines the leaves 
of sweet gum. 
The larvae of Parectopa robiniella Clem. feed in the leaves of 
black locust, forming triangular, blister-like mines. 
Callisto geminatella (Pack.), the unspotted leaf miner, occurs 
throughout the Northern States, west and south to Colorado, Vir- 
ginia, and Arkansas. Its hosts are apple, quince, pear, sour cherry, 
wild cherry, plum, and hawthorn. Eggs are laid on the undersides 
of the leaves, and the larvae devour all of the tissues between the 
upper and lower surfaces of the leaves. Four generations per year 
have been recorded in Virginia. 
Gracillaria negundella Chamb. occurs throughout eastern 
America west to the Prairie Provinces of Canada and feeds on 
boxelder. Early instar larvae feed within mines in the leaves. A 
partly grown larva vacates its mine and moves to the tip of a 
lobe of the leaf, which it then turns over and attaches to the 
lower surface with silk, thus forming a shelter. It then feeds from 
within the shelter. There appears to be at least two generations 
F-506745 
FIGURE 163.—Small - track 
mines of Phyllocnistis pop- 
uliella, the aspen leaf 
miner. 
408 
