Crystal cell pattern modification in a melanotic tumor strain ofDrosophila melanogaster

Summary 3rd instar larvae of the melanotic tumortu-pb strain ofDrosophila melanogaster hold a lower number of free-circulating crystal cells in their hemolymph than the wild type ones. This pattern could result from an abnormal retention of mature crystal cells in the hematopoietic organs, as the strong hemocyte melanization inside the lymph glands of heat-treatedtu-pb larvae seems to demonstrate. Melanotic tumor formation and modification of the crystal cell pattern may be related.