THE EXCRETORY ORGANS
The abdomen of the butterfly contains a number of slender Malpighian tubules, in contact with the blood contained in the various cavities. These tubules extract waste matter from the blood, functioning just as kidneys do in the higher animals. The butterfly has no bladder or urethra, however; the Malpighian tubules empty into the small intestine, and the urine passes out of the body with the fecal matter.