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 0003-0090 7730159 FAMILY BAETIDAE Two baetids were scanned to investigate developmental changes. These are two separate specimens, not the same specimen scanned twice, as done in beetles by Lehmann et al. (2021) . Tracheal morphology between subimago and adult is strikingly consistent, apart from the single alimentary air sac in the adult (vs. divided in subimago), indicating that tracheal development is essentially complete by the subimago stage.