I compare Malaise trapping to rearing as methods for collecting Ichneumonidae in Guanacaste, Costa Rica. In total, 6707 Ichneumonidae were collected in the one year of Malaise trapping, while 2193 were collected in approximately 22 years of rearing. Malaise trapping found a total of 18 different subfamilies, while rearing yielded a total of 13 subfamilies. At the species level for subfamily Pimplinae, Malaise trapping yielded a total of 28 species (375 specimens), while rearing yielded a total of 13 species (108 specimens). Of these, six species were found by both methods, meaning that 22 were found only by Malaise trapping and seven were found only through rearing. I conclude that Malaise trapping is a more efficient way of collecting Ichneumonidae quickly than rearing. I also attempt to determine whether rainfall, host abundance and phenology, or other factors influence the magnitude and timing of flight activity of Ichneumonidae, as measured by Malaise trap catches. To this end I compare across three sites with differing amounts of yearly rainfall in Guanacaste, Costa Rica. Neither rainfall nor host abundance clearly has a significant effect on the magnitude and timing of ichneumonid flight activity, although there is some evidence that host abundance may play a role.