Confocal laser scanning micrographs of hemipteran insects showing the articulation between the “<i>helmet</i>”, head and T2 tergum and the structure of PFE.

<p>A, B: <i>Ceresa</i> sp. (Membracidae) A: Head-“<i>helmet</i>” and “<i>helmet</i>”-T2 tergum joints, sagittal section, anterior left, detail of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0030137#pone-0030137-g006" target="_blank">Fig. 6B</a>. B: Body, sagittal section, anterior to the left. C–E: <i>Leptocoris trivittatus</i> (Coreidae). C: Head-“<i>helmet</i>” and “<i>helmet</i>”-T1 joint, sagittal section, anterior to the left, detail of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0030137#pone-0030137-g006" target="_blank">Fig. 6D</a>; D: Body, sagittal section, anterior to the left. E: PFE, sagittal section; F: <i>Atymna querci</i> (Membracidae), 1st thoracic spiracle with <i>pteralium</i> ( = prepectus). Abbreviations: 16 = Occlusor muscle of 1st thoracic spiracle; 19 = 1st mesopleuro-mesonotal muscle; dl = dorsal layer; fb = fat body cell-like structures; h = head; ism1,2 = intersegmental membrane between T1 and T2; ismh,1 = intersegmental membrane between head and T1; PFE = posterior flattened evagination of T1; pre = prepectus; sp2 = 1st thoracic spiracle; T1 = 1st thoracic segment; T2p = T2 postnotum; T2t = T2 tergum; vl = ventral layer.