Figures 107 (lateral), 108 (dorsal), 109 (ventral) Plates 64 (lateral), 65 (dorsal), 66 (ventral) The P. americana specimen here was scanned early in the study, frozen to - 20 ° C rather than - 80 ° C, and at relatively coarse resolution (38.6 µm, specimen approximately 3.5 cm in length). Some fluid infilling likely occurred due to the freezing to - 20 ° C, but sufficient detail is present to assess homology of major tracheae and discern substantial visceral tracheal anatomy. Although not described in detail, Blaptica was used as a comparison to infer the likely presence of thoracic tracheae in Periplaneta, in particular branching patterns from the mesothoracic spiracle. The thorax features a network of bandlike visceral tracheae along the dorsum and venter, connecting in various locations throughout. This morphology, combined with the long, broad coxae reminiscent of silverfish, obscures internal thoracic tracheal structures in two-dimensional views. The hypognathous position of the head also results in ventral tracheal views of the thorax being obscured; see figure 110 for a ventral view with head and leg tracheae removed. Periplaneta has large air spaces in the coxae, and jumping has been filmed at high speed by Smith (2022). The scan here is of relatively coarse resolution (38 µm); it is possible muscle tracheae could be observed at higher resolutions or with contrast-enhancing stains such as iodine or phosphotungstic acid (Gignac et al., 2016). DESCRIPTION: HEAD: H-DCT and H-VCT present, branching into head capsule in highly networked cagelike arrangement. Mouthparts, H-Ant, and H-Oc determined, but networked nature of head morphology, combined with some apparent fluid infilling, makes assessing homology difficult. Readers are directed to 3 D models in the supplementary digital data. THORAX: T 2 - S with five branches: H-DCT, H-VCT, T 2 - DB, T 2 - AWL, and T 2 - VB. H-DCT and H-VCT both anteriad, curving slightly medially, with H-DCT proceeding along dorsum and H-VCT along venter. T 1 - AL branching ventrad off H-VCT. T 2 - DB short, splitting anteriad into T 2 - DLT and posteriad as network of cagelike T 1 - DVi along pronotum. T 2 - AWL posteriad, with T 2 - W-c-r splitting dorsad and posteriorly; T 2 - AWL splits into T 2 - AL extending into midleg and T 2 - Wbr, partial in this scan but likely present between T 2 - S and T 3 - S. T 2 - VB likewise short, bifurcating into T 2 - VC directly ventrad and T 2 - VLT posteriad. T 2 - VL branching posteriad close to T 2 - S, extending into midcoxa and T 2 - L; T 2 - VLT continuing posteriad to link with T 3 - S. T 3 - S with n branches: T 2 - PWL, T 3 - DB, T 3 - AWL, T 2 - VLT, and T 3 - VLT. T 3 - VB not visible but may be very short. T 2 - PWL anteriad from T 2 - S, bifurcating into T 2 - Wbr anteriad and curving posteriad as T 2 - PL, joining with T 2 - AL from anteriad and extending into mid-leg. T 3 - DB mediad and slightly ventrad, curving posteriorly before extending along dorsum to join with small T 2 - DLT anteriad and larger T 3 - DLT posteriad; T 3 - DC visible at this junction. T 3 - AWL posteriad, with T 3 - W-c-r splitting dorsally; T 3 - AWL continues as T 3 - AL posteriorly and ventrad into hind leg. T 2 - VLT mediad, connect- ing anteriorly to T 2 - S. T 3 - VLT mediad and slightly posterior, connecting to A 1 - S via A 1 - VB. ABDOMEN: Abdomen featuring numerous visceral tracheae throughout. A 1 .. 8 - S present. A 1 - S modified from A 2 .. 8 - S, with three branches: T 3 - PWL, A 1 - DB, A 1 - VB. T 3 - PWL anteriad and slightly mediad, curving posteriorly and joining with T 3 - AL and extending into hind leg; T 3 - Wbr branching from T 3 - PWL at apex of curve and extending anteriad to T 3 - S. A 1 - DB runs mediad, linking with T 3 - DLT anteriad and A 1 - DLT posteriad; A 1 - DB partial in this scan, likely due to fluid infilling (A 1 - DB present in B. dubia and G. portentosa). A 1 - VB mediad and slightly ventrad, extending along venter to A 1 - VC, connecting to A 1 - VLT posteriad; A 1 - MLT posteriad from A 1 - VB. A n - MLT runs straight, extending posteriad and much smaller than thoracic T 3 - VLT. A 2 .. 7 - S branching all similar: A n - DB, A n - VB, and A n - MLT. A n - DB beginning small, expanding into bandlike trachea and intersecting with A n - DLT sections anteriorly and posteriorly in Y-shaped junctions; A n - DC absent. A n - MLT wide and almost bulblike, connecting abdominal spiracles along lateral margin of body wall. A n - VB much smaller and apparently fluid infilled in several spiracles, extending along venter to join with straight A n - VLT anteriad and posteriad in T-shaped junction. A 4 .. 8 - S with numerous visceral tracheae; readers are encouraged to view 3 D models in supplementary digital data.
Sumber: COMPARATIVE ANATOMY OF THE INSECT TRACHEAL SYSTEM PART 1: INTRODUCTION, APTERYGOTES, PALEOPTERA, POLYNEOPTERA