none Heliothis virescens; HYMENOPTERAN-PARASITES; Microplitis croceipes; Parasite behaviour patterns, spring Microplitis croceipes; ACTIVITY-PATTERNS; Time budget & periodicity in presence of lepidopteran host; LEPIDOPTERAN-HOSTS; Heliothis virescens; Parasite behaviour patterns, spring. Microplitis croceipes (Cresson) females were observed between 06:00 and 20:00 hours in cages containing spring host plants infested with Heliothis virescens (F.), tobacco budworm, larvae. Cages contained Geranium dissectum L. and Trifolium incarnatum L. in plantings of equal area, each infested with 50 H. virescens larvae. A time budget for the various behaviors exhibited by the wasps was obtained. In order of decreasing time spent, M. croceipes females were observed to exhibit standing still, searching on plant surface, preening, oriented flight, general flight, and walking. The proportion of time spent preening increased over the day. Oriented flight, general flight, searching, and walking peaked in the morning between 09:00 and 12:00 hours. Oriented flight, general flight, and walking showed minor increased in the afternoon. Microplitis croceipes females spent significantly more time preening, orienting to, and walking and searching on clover than on geranium. However, there was no difference in time spent standing still on geranium or clover. Significance of these findings for development of effective augmentative release strategies is discussed.