The immunity of Drosophila relies on a variety of defenses cooperating to fight parasites and pathogens. The encapsulation reaction is the main hemocytic response neutralizing large parasites like endophagous parasitoids. The diversity of the mechanisms of immunoevasion evolved by Asobara parasitoids, together with the wide spectrum of Drosophila host species they can parasitize, make them ideal models to study and unravel the physiological and cellular aspects of host immunity. This chapter summarizes what could be learnt on the cellular features of the encapsulation process in various Drosophila spp., and also on the major role played by Drosophila hosts hemocytes subpopulations, both in a quantitative and qualitative manner, regarding the issue of the immune Asobara-Drosophila interactions. BR Parasites diseases and disorders. Parasites. Insect parasites. Hosts. Insect hosts. Immunology and repair mechanisms. Tissue reactions. Drosophila (Drosophilidae): Host; Asobara (Braconidae): Parasite. Asobara: Dipteran hosts, Drosophila, Host parasite relationships, host cellular immune strategies, larva; Drosophila: Hymenopteran parasites, Asobara, Host parasite relationships, Immune like reactions, Antiparasitic cellular immune strategies, Encapsulation, Encapsulation process. ST Animalia, Arthropoda, Insecta, Diptera, Brachycera, Cyclorrhapha, Drosophilidae; Animalia, Arthropoda, Insecta, Hymenoptera, Apocrita, Terebrantia, Ichneumonoidea, Braconidae. Arthropods; Hymenopterans; Insects; Invertebrates; True Flies. none