THE HEMOCYTES OF THE MEALYBUGS PHENACOCCUS-MANIHOFI AND PLANOCOCCUS-CITRI (INSECTA, HOMOPTERA) AND THEIR ROLE IN CAPSULE FORMATION

Hemocytes of Phenacoccus manihoti and Planococcus citri were studied t o determine general ultrastructure, phenoloxidase activity, and the pr esence or absence of a glycocalyx. Prohemocytes, oenocytoids, and gran ular hemocytes of types 1 (GH1), 2 (GH2), and 3 (GH3) were observed in P. manihoti. In P. citri we observed only GH2 and GH3 (macrophage-lik e cells). In addition to these hemocyte types, other cells that we bel ieve to be fat-body cells were also observed free in the hemolymph. Th ere was evidence of phenoloxidase activity in GH2 and GH3. The intensi ty of this reaction increased after parasitization of P. manihoti by t he wasp Epidinocarsis lopezi. In most hemocyte types the glycocalyx wa s very little developed. In P. manihoti, lysis of hemocytes was observ ed in the vicinity of the parasitoid larva, leading to the formation o f a capsule.