[Tumors in insects]

The spontaneous tumors in insects are the result of an aggregation of hemocytes. The tumors appearing in Locusta migratoria and Leucophaea after severing the gastric nerves originate from abnormal proliferation of the epithelial cells, particularly in the regenerative nidi in the midgut wall. These tumors can be transmitted by an injection of hemolymph from tumorous animals, of crushed tumor homogenates and cell-free extracts and of ribonucleic acid extracted from tumorous organs.