On the hardening of the cuticle of insects

Abstract

Figure 1. Transverse section through dorsal wall of abdomen of larva of Ephestia kuehniella , showing a partially pupated area. Treated for 24 hr. with 10% ammoniacal silver oxide. (× 300.) Figure 2. Psilopa petrolei . Section of larval cuticle to show spine. Iron haematoxylin. Note that the spine has stained right up to the tip. (× 250.) Figure 3. Calliphora erythrocephala . Section of larval cuticle to show spine. Iron haematoxylin. Note that the distal part of the spine has not stained. (× 250.) Figure 4. Calliphora erythrocephala . Transverse section of larval cuticle. Ammoniacal silver oxide for 24hr. Note that only the epicuticle has reduced the solution. (× 100.) Figure 5. Calliphora erythrocephala . Transverse section of fresh puparium. Ammoniacal silver oxide for 24hr. Note the heavy reduction in both exocuticle and epicuticle. (× 100.)