When flies were maintained on sucrose, allatectomized or had the corpus allatum-cardiacum complex removed, ( Z)-9-tricosene ( Z9–23:HY) was present both internally and externally. Ovariectomy resulted in a significant reduction in the amount of both internal and external Z9–23:HY, and an increase in the amount of the major alkene, ( Z)-9-heptacosene ( Z9–27:HY) when compared with the controls. The surgical treatments did not prevent the appearance of Z9–23:HY on the surface, but there was 10–19 times more Z9–23:HY found internally than externally. The amount of Z9–27:HY was about equally distributed between the internal and surface lipids and was not altered significantly by allatectomy, removal of the corpus allatum-cardiacum complex or ovariectomy. When ovariectomized flies were injected with 20-hydroxyecdysone or ecdysone, Z9–23:HY synthesis was induced. Ecdysone was about three times more effective in stimulating Z9–23:HY synthesis than was 20-hydroxyecdysone. As the amount of Z9–23:HY increased, Z9–27:HY decreased. Flies maintained on sucrose had more Z9–23:HY on the surface and less internally when compared with the protein-fed flies and had ratios (external/internal) of 0.53 and 0.18, respectively. Treating sucrose-fed flies with methoprene resulted in a nearly equal distribution of Z9–23:HY between the internal and external lipids and resulted in a ratio of 0.88 by 72 h post-treatment. Thus, flies on the sucrose diet had a ratio that was three times larger than the protein-fed flies, and when sucrose-fed flies were treated with methoprene the ratio was five times larger.