The structure of the lymph glands ofDrosophila larvae.

1. A detailed morphological and histological description is given of the lymph glands of late third instar wild type larvae. 2. In the late second instar of the wild type the lymph glands release some or their cells and these form the imaginal disc mesoderm, the lymph hearts, and other structures. The formation and the functioning of the lymph hearts are described. 3. It is argued that blood cells do not exist in theDrosophila larva.