Metaphycus flavus (Howard) (Hymenoptera: Encyrtidae) is a facultatively gregarious endoparasitoid of soft scales (Hemiptera: Coccidae). When it develops in superparasitised hosts, the larvae often attack and consume brood mates six or more days post oviposition. Under our laboratory conditions (25±1°C and 14 hours of light followed by 18±1°C and ten hours of darkness in 50–70% R.H.), M. flavus eggs hatched three days after oviposition. Measurements of the mandibles and tentorium indicate there are four larval instars, and M. flavus reaches the fourth instar by day six post oviposition, and pupates on day eight. Thus, cannibalism among M. flavus larvae occurs during the fourth instar. During this instar, M. flavus larvae separate from their attachment to the scale cuticle, to which they were tethered by a respiratory structure during the previous three larval instars. Once detached, they are free to move within the scale, which increases the probability of larval encounters and aggressive behaviours. Moreover, the mandibles of the fourth instar are better adapted for fighting than are those of the first three larval instars, since they are larger and more sclerotized. The cranium and mouthparts of M. flavus have four different types of sensory organs, some of which are almost certainly olfactory, an unexpected function for a larva that presumably is surrounded by an aqueous medium where gustatory sensilla would seem to be more appropriate. The cranium also bears two pairs of what appear to be secretory pores.

The European fruit lecanium (EFL), Parthenolecanium corni Bouché (Hemiptera: Coccoidea), is a common and harmful soft scale, which attacks Fraxinus oxycarpa Willd. and other ornamental and orchard plants in Tbilisi, Georgia. This study investigates the phenology, degree of plant damage and effect of parasitoids on this scale in Tbilisi, a densely populated area. We present data on the 32 species of chalcidoid parasitoids recorded from EFL in Georgia and south-eastern Europe. The scale is heavily parasitized in Tbilisi, but we did not find any variation in seasonal abundance. The most common parasitoid of EFL was Blastothrix longipennis (Hymenoptera: Encyrtidae).

Epidinocarsis lopezi proved to be an efficient biological control agent of the cassava mealybug (CM), Phenacoccus manihoti, despite apparently low parasitization rates. Laboratory experiments indicated that its killing power at higher temperatures was two to three times higher than the per cent mummy formation suggested. Following an attack by an E. lopezi female some CM hosts were killed through host feeding and some through successful development of the parasitoid larva, processes which both benefit the parasitoid. If the host was found unsuitable, no egg was laid, and the CM survived the attack. Other CM died from the wasp attack without forming a mummy. This mortality is attributed to mutilation and unsuccessful larval development of E. lopezi. Most ovipositions induced a defence reaction by the host that lead to melanization. This process involved mainly wound tissue, sometimes partial encapsulation of the tail end of the parasitoid larva, and infrequently complete and fatal encapsulation of the parasitoid larva.