Published online by Cambridge University Press: 31 May 2012
Laser treatment of larval and pupal stages within cocoons of Neodiprion sertifer (Geoff.) requires an accurate assessment of viability and the antero-posterior alignment of the cocoon content. The use of the candling technique to assess qualitative features of avian eggs depends on the translucency of the egg shell and the differences in light transmission by other elements within it (Romanoff and Romanoff 1949). Transmitted-light methods have been employed for insects within cocoons by Cushman (1913) and Hanna (1935). A type of candling technique different from previous methods and which was developed in the Zoology Department, University of Guelph, enables N. sertifer cocoon content to be ascertained and is herein described.