On the Production and Meaning of Metamorphosis-Promoting Hormones During the Larval Development of Drosophila by MARGUERITE VOGT

A. Introduction ............................................................................................................................395 B. Materials and Methods............................................................................................................396 C. Experimental Part.. .................................................................................................................397 I. Promotion of metamorphosis process by the ring gland of the first and early second larval stage.............................................................................................. 397 a) Pupation processes ...................................................................................................398 b) Imaginal differentiation processes........................................................................... 399 II. Different behavior of various aged ring glands .................................................................401 a) with implantation in isolated abdomens of the third larval instar............................ 401 b) with implantation into unligated larvae of the second and third larva of instar........................................................................................................................ 406 III. Stimulating developmental processes occuring during the development of larvae by implanted glands ..........................................................................................418 a) Findings on eye antennal imaginal discs: l. after pupation of the host abdomens ....................................................................418 2. in host abdomens blocked from pupating .......................................................... 427 b) Findings on testicles .............................................................................................. 431 Appendix. Supplementing remarks on the hormonal control of testicle development ........................................................................................................... 432 IV. The ring gland thigh cells as promoters of both certain more larval development procedures and of the puparium formation of using metamorphosis processes ....... ..436 D. Discussion .............................................................................................................................439 E. Summary................................................................................................................................444 F. References ..............................................................................................................................445