Unusual sex chromosome inheritance in six species of small ermine moths (Yponomeuta, Yponomeutidae, Lepidoptera)
First meiotic division in females and males of Yponomeuta evonyrnellus (L.), Y. cagnagellus (Hiibner). Y. rnalinellus Zeller, Y. padellus (L), Y. rorellus (Hiibner) and Y. gigas Rebel was studied in the light microscope. In the heterogametic females the sex chromosomes were found to be associated in a sex chromosome trivalent. The sex chromosome trivalent, written AA W Z, consisted of a W‐chromos
