parasitoid complex of Euxoa ochrogaster (Guenee) (Lepidoptera: Noctuidae)

The red-backed cutworm, Euxoa ochrogaster (Guenee) is a well-known, destructive ground cutworm native to the prairie provinces of Canada. The purpose of this study is to provide a method of identifying some of the immature stages of the parasitoids of the redbacked cutworm. Some groups of parasitoids are difficult to identify to species as adults but may be identified using morphological or behavioural characters of immature stages. The advantages of recognizing the immature stages of the parasitoids of any host species are: 1. If research with live adult parasitoids is necessary, identification using the remains of the immature stages prevents damage to the living specimens. 2. It is not necessary to rear either the host or the parasitoids to maturity to obtain data on the host-parasitoid relations. This allows analysis of host specimens which died, and of hosts killed to enlarge a sample size when there was no time to rear all the hosts or parasitoids to .maturity. 3. Super-, hyper-, or multiple parasitoid attack can usually be recognized only by the dissection of host material before any of the parasitoids can mature and emerge. Analysis of inter-specifi c and intra-specific competition of parasitoids as well as the interactions with predators and disease is possible from the results of such dissections. The term parasitoid is used in this paper rather than parasite which is usually used when referring to entomophagous groups which attack single host units. The need for the term parasitoid arises from the fact that ecologically the action of such entomophagous species is different from that of either predators or true parasites. Doutt (1964) outlined the ways in which parasitoids differ from parasites.