[The metamorphosis of protein pattern of haemolymph and fat body inEphestia kühniella Z.]

1. The ontogenesis and the control of stage specific changes in the spectra of the soluble proteins of the haemolymph and the fat body ofEphestia kühniella were examined. 2. The total protein concentration of the haemolymph is subject to considerable fluctuations during postembryonal development. It rises during the 5th larval stage and then drops again during molting. During the 6th larval stage up to the beginning of the prepupal stage it maximizes at 3 times its original amount at a concentration of 100 mg/ml. After a decrease during the prepupal phase a new peak occurs during the pupal stage. In the young imago a minimum is observed. From measurements of the haemolymph volume during the last larval molt and the last larval stage the absolute amount of blood protein could be calculated. In general it follows the concentration curve. 3. By means of cellogel electrophoresis the haemolymph proteins of young prepupae can be separated into 10 different fractions. In addition to yellow and bluegreen chromoproteids, lipo- and glycoproteids can be found. In homogenates of whole animals and organs blood proteins were identified by means of their electrophoretic mobility and their immunologic properties. 4. During development some of the haemolymph protein fractions show a distinct stage specificity and individual fluctuations of concentration. In further investigations two bands (i.e. 2 and 3) were of main interest because of their extremly different ontogenetic fates. 5. In the course of the prepupal phase band 2 disappears almost completely from the haemolymph, whereas 3 is hardly reduced. At the same time the fat body accumulates zone 2 much more than 3. The temporal correlation of these changes in both organs and the fact that the concentration of the fractions 2 and 3 in homogenates of whole animals does not change at the same time indicates a selective sequestration and accumulation of blood proteins by the fat body. In gut homogenates neither of the two fractions was found. 6. At the beginning of metamorphosis the concentration of band 2 in homogenates of whole animals remains constant. But in the blood it passes a new maximum synchronously to the histolysis of the fat body. Zone 3 slowly decreases in homogenates of whole animals and haemolymph. In the imago neither of the two fractions was detected. 7. By means of thoracic ligatures in the abdomina of L6T7-larvae (shortly before the prepupal stage) the disappearence of the band 2 from the haemolymph and the accumulation of this fraction in the fat body can be prevented. Both connected processes take place in isolated abdomina of young prepupae (A2) but not to the same intensity as in normal development. 8. By injecting ecdysone (0.125-1.000 μg) a complete impoverishment of the haemolymph of band 2 can be induced in the isolated abdomina of A2 prepupae. 9. The accumulation of blood proteins in the fat body is correlated with the appearence of histologically provable albuminoid granules.