Profenusa thomsoni (Konow), the ambermarked birch leafminer, possibly an 
introduced species from Europe, 1s widely distributed in Quebec, Maine, Vermont, 
Connecticut, Ontario, Wisconsin, Illinois, and Manitoba. Its hosts are gray, paper, 
and yellow birches. This leafminer is one of the four sawflies that feeds in leaves of 
Betula spp. (1097). In Ontario, female adults were observed in late July and early 
August. Eggs are laid in the tissues of leaves. The larvae mine the tissues, forming 
light-colored blotch mines. Up to 40 larvae inhabit a single mine. When all of the 
tissues of a leaf are consumed, all of the larvae, regardless of age, vacate the mine 
and drop to the ground. Of these, only those in the latter part of the fifth instar are 
able to enter the soil and survive. In light infestations, sucker growth up to about 
1.2 m tall in shaded locations is preferred. In contrast, trees up to 10.7 m tall in all 
types of habitats are attacked in heavily infested areas. Damage is not considered 
serious because defoliation occurs late in the season (S2/). 
Profenusa alumna (MacGillivray) has been observed mining the leaves of oak, 
primarily red oak, from Maine to Virginia west to Wisconsin and [llinois. Full- 
grown larvae are about 6 mm long and have prognathous, octagonal heads more 
than twice as wide as long. Winter is spent as prepupae in cells in the duff. 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. Although males have not been collected in Maine, 
they have been taken in other areas of its range (/097). 
Profenusa canadensis (Marlatt), the hawthorn leafmining sawfly, has been re- 
corded mining the leaves of hawthorn and cultivated cherry. It 1s widely distributed 
in eastern North America (/097). Serious infestations have occurred in Mas- 
sachusetts and New York. P. /ucifex (Ross) attacks white oak in Maine, New York, 
and Illinois, and bur oak in Ontario (737). 
Messa populifoliella (Townsend), the poplar leafmining sawfly, mines the leaves 
of poplar from New Brunswick southwestward to New Mexico and west to Califor- 
nia, also in South Dakota and Manitoba (/097). In New Brunswick, adults are 
present the latter part of May. Females oviposit generally near the leaf tip. Larvae 
feed for 2 to 3 weeks, making blotch mines. They then drop to the soil to overwinter 
and pupate (/2/7). 
The pear sawfly, Caliroa cerasi (L.), an introduced species, occurs from coast 
to coast in southern Canada and the 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 serviceberry. Full-grown 
larvae are tadpole-shaped, sluglike, 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 lined with a substance secreted by the larvae. 
Pupation occurs in June. Eggs are deposited singly in small semicircular slits cut in 
the leaf tissue. The larvae feed mostly on 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. Reproduction is parthenogenetic (/097). Females appear in 
2 or 3 weeks and lay eggs. Larvae of this generation are present in August and 
September. When they become mature, they also drop to the ground. There are two 
generations per year throughout most of the range of this sawfly. 
The scarlet oak sawfly, Caliroa quercuscoccineae (Dyar), has been recorded 
from scarlet, black, pin, and white oaks from Maine to North Carolina west to 
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