© 2015 by Taylor & Francis Group, LLC. Lepidoptera, moths and butterflies, is the second species-richest insect order, which comprise more than 130,000 species (Beccaloni et al. 2003). The holokinetic chromosome nature of Lepidoptera as well as Trichoptera (cf., caddis flies: sister clade of Lepidoptera) is shared with Hemiptera (aphids and bugs) within Insecta (see Section 6.1.2). However, sex chromosome systems of Lepidoptera and Trichoptera are female heterogamety (WZ/ZZ, female/male), unlike male heterogametic system (XX/XY, female/male) of all others.