The koinobiont endoparasitoid Diaphorencyrtus aligarhensis (Shafee, Alam & Agarwal) (Hymenoptera: Encyrtidae) is an imported biological control agent being released in Florida against the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae). The eggs and early larvae were found free floating within the hemocoel. Larvae were soft bodied with no observable hairs, bristles, or external appendages, such as anal vesicles, in any instar. By the third instar, larvae had begun attaching to nymphal tissues by anal secretions that provided a means of orienting within the host nymph. The penultimate and last-instar larvae were found with their posterior anchored in the head—thoracic region of the host with their head oriented toward the posterior of the host nymph. Before the beginning of the prepupal stage, the host nymph was turned into a mummy and glued to a plant surface, apparently requiring some secretions from the wasp larva. Development from oviposition to adult eclosion of D. aligarhensis took ≈16 d at 25°C when oviposition occurred in second-through early fourth-instar nymphs, although this time was shortened by 4 d (25%) when the wasps oviposited in mid-fourth-instar D. citri nymphs. This reduction in developmental time did not affect wasp fertility or life span and may offer a significant approach to improved rearing of this wasp for augmentative releases to control the Asian citrus psyllid.