Some experimental observations on the cryptonephric malpighian tubules.

Imago of Tenebrio, Dermestes (Coleoptera) and Lepidopterous caterpillars Pieris and Galleria were observed for the general physiology of the cryptonephric Malpighian tubules. Injection of dyes were made. The dyes were taken only by the free portion of the Malpighian tubules. Reassociated Malpighian tubules do not take dyes from the haemoly mph. They are secretory, but not excretory. The perinephric membrane in the Lepidoptera is impermeable to the dyes.