The Unknown Larva of Anodocheilus Babington (Coleoptera: Dytiscidae: Hydroporinae: Bidessini): Description of A. maculatus Babington and Chaetotaxic Considerations

Larval morphology of the New World dytiscid genus Anodocheilus Babington is studied. For this purpose, the three larval instars of A. maculatus Babington are described and illustrated for the first time, with particular emphasis on the morphometry and chaetotaxy. First-instar larva of Anodocheilus can be distinguished from those of Liodessus Guignot and Amarodytes Régimbart (the only other bidessines known as first instars) in its more elongate siphon. All Bidessini genera known as first-instar larvae are characterized by the absence of pore ABc. This pore is consistently present in the remaining hydroporines. Third-instar larva of Anodocheilus has an elongate siphon and a short first urogomphomere. These features link the genus to Uvarus Guignot and Bidessus Sharp. The remaining known Bidessini genera have a short siphon and an elongate first urogomphomere. The presence of two contiguous pores on a very small bulge in the stipes of Anodocheilus larvae reinforces the hypothesis that hydroporines lost the galea secondarily.