COMPARISON OF THE CHROMATOPHOROTROPIC ACTIVITY OF INSECT CORPORA CARDIACA WITH THAT OF CRUSTACEAN SINUS GLANDS

¹ From the Department of Zoölogy, Northwestern University

1. The corpora cardiaca are the organs in the head of the insect which are responsible for the formation of a substance which produces a strong concentration of the pigment of the red chromatophores of crustaceans.

2. The corpora cardiaca still have an effect upon isolated red chromatophores of Cambarus when the gland is extracted in 80,000,000 times its volume of Griffeth's solution.

3. Neither the corpora cardiaca nor the corpora allata have any perceptible effect upon the white chromatophores of Cambarus; the latter gland is also without effect upon the red chromatophores.

4. The crustacean sinus glands still have an effect upon isolated red chromatophores when extracted in about 14,000,000 times their volume of Griffeth's solution.

5. The sinus glands of crayfishes produce a dispersion of the pigment of the white chromatophores of Cambarus.

6. The crustacean sinus gland and the insect corpora cardiaca differ qualitatively from one another with respect to their action upon the white chromatophores. With respect to the red pigment-affecting principle, the two glands are similar in that the rate of loss of effectiveness with dilution is the same for both, boiling the extracts inactivates neither, and both glands retain their effectiveness for some time in a desiccated state.