Corpora Allata

glands of internal secretion in insects. Corpora allata are a pair of small, compact glandular organs covered with connective-tissue membrane. They are modified coelomoducts of the maxillary segment of the head and are located behind the brain above the fore-intestine. The function of the corpora allata is regulated by the sympathetic nervous system. They elaborate juvenile hormone, which prevents conversion of the larva to a pupa and to an adult insect and stimulates growth and development of larval organs. In the final larval stage, the action of juvenile hormone gradually diminishes. This is because its concentration in the blood decreases, since the growth of the larval body exceeds that of the corpora allata. Removal of the corpora allata in a larva causes premature metamorphosis into a miniature adult individual. In adult insects the hormone of the corpora allata stimulates maturation of the sex cells.