INTRODUCTION 
The following report deals with some of the forest Lepidoptera of southern Ontario thpi r 
parasites, distribution host trees, period of larval and adult activity, and"” rf infe^Uon a e 
report, is based on the data obtained from the Forest Insect Survey records at Ottawa during the years 1937 
to 1948 inclusive. The compilation of this list has been made possible by the personnel of the Un^ 
Systematic Entomology who determined the material and by the Forest Insect Survey staff at Ottawa. 
T T u, F °r the purpose of this report, southern Ontario comprises the Rideau, Quinte, Trent Lake Simcoe 
^XrSTsS^r 6 Q ' le . Pr T nC1 : 1 f ° reSt dlStrlCtS - Ihere •« - 1 - references to collect 
Federal District Commission territories in the Gatineau (Quebec) area north of Ottawa. The accompanying 
map, showing the counties of southern Ontario, depicts the area referred to in this report aCC ° mpajiying 
r ^ are arranged 111 accordance with McDunnough's "Check List of the Lepidoptera of 
Canada and United States of America" and are also assigned the catalogue numbers from M Species 
described or listed since the check list was published are given a supplementary catalogue n viler 
7 —^ f-° C ^ Br J W ?^ 0 W !; iCh d ° eS not a PP ear ^ the check list but which should be placid between 4431 ’ 
T. contractata and 4432 T, ptisi, is given the number 4431X. 
i ^ P rin ^P trees are bitten in block letters, other host trees are in ordinary type 
Jh system is applicable to most of the 468 species listed except for a few general feeders such as" 
H emerocampa leu costigma and Nptplpphus anUcpia which do not appear to have any special hoS preferences. 
About 50 per cent of the pupae were reared in incubators during the winter; the months of 
nr “if 1 ^ ^ ases ^ are shovm in parentheses. The period of normal adult emergence is based on records 
of adults collected in the field or on material caged under approximately natural conditions. 
An asterisk following the parentheses means that the period of adult activity is based on dates 
recorded with specimens from field-collected material preserved in the Canadian National Collection. 
. , , . P eri ° d ^ e n larvae, pupae, or adults occur often varies considerably according to the species 
volved, .he locality, and the season. In this report the normal months of larval, pupal, or adult P 
™ eu Inasmuch as most of the forest insect survey material is received in the larval stage, the data 
on the parasites are by no means complete, particularly on parasites affecting the host in the egg and 
late larval or pupal stages. 6S 
Th ® r ® are probably more species of forest Lepidoptera from southern Ontario than from any 
other part of Eastern Canada, as all the coniferous and most of the deciduous trees found in the east 
occur in southern Ontario, which is also the home of many trees not found anywhere else in Canada. 
