Key to known Nearctic larvae of Ablabesmyia 1. Maxillary palp with 2–3 distinct basal segments (Fig. 5 C–F, H, I)............................................... 2 - Maxillary palp with 5–6 distinct basal segments (Fig. 5 B, G).................................................. 12 2. Ligula with apices of teeth even, median and inner teeth truncate with paler apices; procercus 5.0–7.0 times as long as wide, posterior parapod without distinct dark claw, with extensive lateral hooklets on shaft........... A. (Asayia) annulata (Say) - Ligula with apices of teeth concave arc; procercus 2.0–4.0 times as long as wide, 1–3 distinct dark claws on each posterior parapod (except in A. (Karelia) philosphagnos).............................................................. 3 3. Head capsule with two ventromesal dark spots larger one closer to the middle, the other smaller near the posterior margin and posterior parapod without sharply bent tooth..................................... Ablabesmyia (A.) simpsoni Roback - Head capsule with at most a faint mesal-ventral spot near posterior margin or when spots distinct posterior parapod with sharply bent tooth..................................................................................... 4 4. No distinct dark claw on posterior parapods and maxillary palp with 2 segments (Fig. 5 D)............................................................................................... A. (Karelia) philosphagnos Beck et Beck - 1–3 distinct dark claws on posterior parapods............................................................... 5 5. Maxillary palp with 2 distinct segments.................................................................... 6 - Maxillary palp with 3 distinct segments.................................................................... 9 6. Posterior parapod with 3 darker claws.......................................... A. (Karelia) cinctipes (Johannsen) - Posterior parapod with 1–2 darker claws................................................................... 7 7. One dark claw of posterior parapod distinctly longer than second...................... A. (Karelia) illinoensis (Malloch) - Dark claws of posterior parapod more subequal in length...................................................... 8 8. Ligula with inner teeth outcurved (Fig. 4 J); head capsule about 1.3–1.4 mm long; segments of maxillary palp subequal in length (Fig.5 E)........................................................ A. (Karelia) pulchripennis (Lundbeck) - Ligula with inner teeth relatively straight; head capsule less than 1.3 mm long, apical segment of maxillary palp slightly longer than basal segment............................................................ A. (Karelia) peleensis (Walley) 9. Ligula with apices of teeth in approximately straight line..................................... A. (A.) janta (Roback) - Ligula with apices of teeth in concave arch................................................................ 10 10. Ligula more than 80 µm long, mandible more than 155 µm long............................................... 11 - Ligula less than 80 µm long, mandible generally less than 155 µm long.. A. (A.) parajanta Roback, A. (A.) rhamphe Sublette 11. Posterior parapods each with 1 dark claw; head capsule sometimes with distinct mesal-ventral spot; ligula with inner teeth dis- tinctly outcurved (Fig. 4 L)........................................................... A. (A.) basalis (Walley) - Posterior parapods each with 2 dark claws; ligula with inner teeth at most slightly outcurved (Fig. 4 M)................................................................................................. A. (A.) monilis auct nec L. 12. Head capsule with large dorsal, anteromesal, dark brown spot; posterior parapod without sharply bent tooth............................................................................................. A. (A.) hauberi Beck et Beck - Head capsule without dark brown apicoventral rectangle, posterior parapod with or without sharply bent tooth........... 13 13. All teeth of ligula completely dark; posterior parapods each with one distinctly dark claw and one additional claw which may be slightly darkened, with sharply bent tooth, AR 4.5–5.2..................................... A. (A.) aspera Roback - Apices of 3 median teeth of ligula pale, posterior parapods each with 2–3 distinctly dark claws, without sharply bent tooth, AR 3.8–4.6........................................................................... A. (A.) mallochi (Walley)

Published as part of Saether, Ole A., 2011, Notes on Canadian Ablabesmyia Johannsen, with keys to known Nearctic immatures of the genus (Diptera: Chironomidae), pp. 43-62 in Zootaxa 3069 on pages 46-47, DOI: 10.5281/zenodo.279010