Both larval and elytral dorsal cuticle are composed of distinct layers including the envelope, epicuticle and procuticle. The procuticle consists of a number of horizontal, chitinous laminae. In addition, there are numerous pore canals running transverse to the laminae in elytral cuticle, as well as to the apical plasma membrane. The canals extend from the apical plasma membrane to the epicuticle region and contain a core of pore canal fibers. EN, envelope; EP, epicuticle; PRO, procuticle; PC, pore canal; PCF, pore canal fiber; APMP, apical plasma membrane protrusion. Scale bar = 2 μm. From Noh et al., (2014) [21].