Adults appear in the spring and the female lays her eggs on the 
upper surfaces of the leaves. The larvae bore into the leaf and 
mine the tissues, causing blotching and severe browning. Heavily 
infested leaves may drop by September, leaving bare branches in 
the top of the tree. 
Profenusa canadensis (Marlatt) has been recorded mining the 
leaves of hawthorn and cultivated cherry in Massachusetts, New 
York, and Wisconsin. Serious infestations have occurred in Mas- 
sachusetts and New York. P. lucifex (Ross) attacks white oak in 
Maine and bur oak in Ontario. 
Messa populifoliella (Townsend) mines the leaves of poplar 
from New Brunswick southwestward through the United States 
to Arizona. 
The pear-slug, Caliroa cerasi (L.), an introduced species, occurs 
from coast to coast in southern Canada and northern United 
States. Although best known as a pest of cherry and pear in the 
United States, it also feeds occasionally on hawthorn, plum, 
quince, mountain ash, black cherry, and shadbush. Full-grown 
larvae are tadpole-shaped, slug-like, and about 12 mm. long. The 
body is covered with a shiny, olive-green material secreted by the 
larva. 
Winter is spent in earthen cells or in cocoons composed of 
grains of earth and a substance secreted by the larvae. Pupation 
occurs in June. Eggs are deposited singly in small semi-circular 
slits cut in the leaf tissue. The larvae feed mostly from the upper 
surface of the leaf, eating the parenchyma only. Heavily infested 
trees appear as if scorched, and their leaves drop prematurely. 
Full-grown larvae drop to the ground and form cells in the soil 
in which pupation occurs. Adults appear in 2 or 3 weeks and lay 
eggs. Larvae of this generation are present in August and Sep- 
tember. When they become mature, they also drop to the ground. 
There are two generations per year throughout most of the in- 
fested portions of the United States. 
Caliroa lineata MacGillivary, the pin oak sawfly, has been re- 
corded in New Jersey, North Carolina, and Missouri. Its hosts 
are pin, white, and various red oaks, preferably pin. Full-grown 
larvae are slug-like, yellowish-green, and about 12 mm. long. The 
head and thoracic legs are shiny black. There appears to be at 
least two generations per year in New Jersey (319). Both larvae 
and adults may be found almost any time from late May or early 
June until late September. The larvae feed on the lower surfaces 
of the leaves, leaving only the upper surface and a fine network 
of veins. Defoliation is usually noticed first in the tops of trees. 
Late in the season heavily infested trees may be completely de- 
foliated. 
Caliroa (near) quercuscoccineae (Dyar) has been recorded 
feeding on pin oak in Massachusetts and North Carolina. Full- 
grown larvae are shiny green and about 12 mm. long. Adults 
appear to be most numerous in October. Eggs are laid in slits cut 
in the lower surface of the leaf. They are placed singly in rows 
along the sides of the midribs and larger veins, and all hatch 
within a few days after being laid. The larvae feed on the epi- 
dermis of the leaf, leaving it almost colorless and transparent. Evi- 
dence of feeding is apparent during late summer. There may be 
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