Peak infestations of adult Amblyomma americanum (L.) ticks on white-tailed deer [Odocoileus virginanus (Boddaert)] occurred in late May, June and early July in 1973 and 1974. Significant nymphal tick infestations were observed from April to October. Peak larval tick infestations occurred in late July and August. The dynamics of the infestation levels were affected by climatic conditions and deer numbers. Repression of repletion of the adult and nymphal tick stages, apparently a response to photoperiod, has survival value in that the subsequent stage after molt does not become an active host-seeker at a time unfavorable for its maximum survival.