COMPARATIVE ANATOMY OF THE INSECT TRACHEAL SYSTEM PART 1: INTRODUCTION, APTERYGOTES, PALEOPTERA, POLYNEOPTERA Author Herhold, Hollister W Author Davis, Steven R Author Degrey, Samuel P Author Grimaldi, David A text Bulletin of the American Museum of Natural History 2023 2023-03-31 459 1 1 184 http://dx.doi.org/10.5531/sd.sp.55 journal article 10.5531/sd.sp.55 eb1717dc-9526-481c-a859-7ca8fd036425 0003-0090 7730159 Anisolabis maritima “Maritime earwig” Figures 44 (lateral), 45 (dorsal, ventral) Plates 24 (lateral), 25 (dorsal, ventral) A greater number of smaller tracheae are visible in the Anisolabis scan than the Forficula scan. As the CT scans for this study specifically targeted tracheal morphology, visualization of internal morphology of organs and internal structures was generally not possible. Therefore, determining the specific tissues supplied by a given trachea is challenging. However, some structures appear to have a particular tracheal morphology, such as muscle fibers and some other structures, and the detail afforded in the Anisolabis scan allows for some possibilities. For example, A 3-VLT-Vi begins by branching from A 3- VLT and proceeding anteriorly. Just before reaching the anterior end of the abdomen; however, A 3-VLT-Vi splits into several smaller tracheae that turn posteriorly to form a cone, most likely the tracheation of a portion of the alimentary canal, possibly the proventriculus. Additional detail is observable in the terminalia, specifically the cerci. As mentioned previously, extensive tracheation of A 7 and A 8 is for musculature controlling the forceps, and two tracheae are seen extending into the cerci. A 8-DLT-Cr is supplied by A 8- DLT , which arcs ventrad and posteriorly into each side of the forceps, and a second trachea A 8-VLT-Cr from A 8- VLT , reaching basically straight posteriad to cross over A 8-DLT-Cr into the cerci. DESCRIPTION: HEAD : H-DCT and H-VCT similar diameter; H-DCTs curve inward slightly such that left and right tracheae nearly touch before turning laterally outward on entry to head capsule; H-VCTs both proceed straight into head. H-DCT with several branches just anterior of cervix: H-DCC, H-DCT-Dvi, H-Oc, and H-Ant. H-DCC present, with several small H-DCC-Dvi fanning laterally and anteriad along head capsule. H-DCT-Dvi runs laterally and dorsad, branching off H-Oc. H-Oc arcing laterally, with several small tracheae extending into eye, then continuing anteriorly and ventrad via H-Oc-Md to link with ventral H-Md; H-Oc-Ant branches off H-Oc into antenna. H-Ant extends anteriorly through head into antenna; H-Ant with multiple tracheae in Anisolabis (H-Md-Ant, below). H-VCT likewise with several branches just anterior of cervix: H-VCT-Vi, H-Ft-Lbr, H-VC, and H-Mx-Md. H-VCT-Vi laterally and dorsad, like dorsal trachea. H-Ft-Lbr anteriad, with H-VC extending medially to link left and right sides; H-Ft branching laterally and anteriad with H-Lbr running directly anteriad. Both H-VC with H-VC-Dvi running directly anteriad. H-Ft-Lbr runs anteriad, with small H-Ft splitting laterally and anteriad, remaining H-Lbr running anteriad. H-Mx-Md runs anteriad and slightly laterally, with several branches: H-Lbm run ventrad, with short H-LbmPlp; H-Mx running ventrad, with short H-MxPlp. Remaining H-Md branch runs anteriad, with H-Oc-Md connection from H-DCT; H-Md-Ant branching dorsally to parallel H-Ant from H-DCT. FIGURE 43. Dermaptera thoraces, dorsal view: A. Forficula , B. Anisolabis . THORAX: T 1-DVi branching from H-DCT closer to T 2- S than in Forficula . T 1-MVi visible. Several T 1-Fm visible. T 3-VL with connection to VLT near A 1-VB connection, forming X-shaped chiasma. ABDOMEN: A 4-DLT-Mvi branching from interior side of A 4- DLT , slightly posterior to junction with A 4-DB on right side of the body but nearly at Y-shaped junction on the left side. Branching of A n -DLT-Mvi from interior side of the dorsal longitudinal trunk varies between left and right side, but general anterior-posterior direction of tracheae is consistent for each segment (see fig. 46 ). A 4-VLT-Vi anteriad, extending through nearly two body segments. Anterior direction of A n - VLT-Vi consistent for Anisolabis . A 8-VLT-Cr and A 8-DLT-Cr extending into forceps.