| Namamyia | Larva - pronotum lateral view | Merritt p. 376 fig. 18.206 |
| Namamyia | Larva - ab1 ventral | Merritt p. 378 fig. 18.214 |
| Narpus | Imago - maxillary palp | Merritt p. 454 fig. 20.282 |
| Narpus | Larva - head dorsal | Merritt p. 449 fig. 20.236 |
| Nectopsyche | Larva - head ventral | Merritt p. 366 fig. 18.114 |
| Nectopsyche | Larva - hind leg lateral | Merritt p. 366 fig. 18.116 |
| Nectopsyche | Larva - case | Merritt p. 366 fig. 18.121 |
| Nectopsyche | larva - case | Pobst - p. 82-b |
| Nectopsyche | Larva - abdomen posterior ventral | Merritt p. 364 fig. 18.109 |
| Nectopsyche | Imago - lateral view | LaFontaine p. 255 - b |
| Nectopsyche | Adult - lateral | Pobst - p. 82-a |
| Nectopsyche | Larva - case | McCafferty p. 270 fig. 14.88 |
| Nectopsyche | Larva - case | LaFontaine p. 255 - a |
| Nectopsyche candida | Larva - larva | McCafferty p. 270 fig. 14.87 |
| Nectopsyche exquisita | Imago - adult | McCafferty p. CP XIII fig. 096 |
| Nectopsyche gracilis (Nectopsyche intervena) | Larva - lateral view | Bouchard p. 130 fig. 10.54 |
| Nematomorpha | Ametabolous - full view | Bouchard p. 13 fig. 2.10 |
| Nemocapnia | Larva - meso & metathorax dorsal | Bouchard p. 82 fig. 6.27 |
| Nemocapnia carolina | Larva - right cercus outer view | Merritt p. 227 fig. 14.33 |
| Nemotaulius | Larva - head dorsal | Bouchard p. 125 fig. 10.42 |
| Nemoura arctica | Larva - pronotum | Merritt p. 227 fig. 14.22 |
| Nemoura trispinosa | Imago - fore wing | Merritt p. 240 fig. 14.107 |
| Nemoura trispinosa | Imago - labium | Merritt p. 240 fig. 14.109 |
| Nemouridae | Imago - fore wing | McCafferty p. 154 fig. 09.03 |
| Neobidessus | Imago - head, pronotum, elytra bases | Merritt p. 424 fig. 20.087 |
| Neochoroterpes | Larva - gill 1 variation a | Merritt p. 141 fig. 11.68a |
| Neochoroterpes | Larva - gill 1 variation b | Merritt p. 141 fig. 11.68b |
| Neochoroterpes nanita (Choroterpes nanita) | Imago - male genitalia | Needham p. 543 c |
| Neochoroterpes oklahoma (Choroterpes oklahoma) | Imago - male genitalia | Needham p. 543 d |
| Neocorixa | Imago - abdominal tergites | Merritt p. 274 fig. 15.23 |
| Neocurtilla hexadactyla | Imago - adult | McCafferty p. 342 fig. 17.03 |
| Neocylloepus | Imago - dorsal view | Merritt p. 454 fig. 20.286 |
| Neocylloepus | Larva - last abd. segs. dorsal | Merritt p. 449 fig. 20.245 |
| Neoelmis | Imago - dorsal view | Merritt p. 456 fig. 20.287 |
| Neoephemera | Larva - head & thorax dorsal | Merritt p. 133 fig. 11.16 |
| Neoephemera | Imago - forewing veins M2 & Cu1 | McClane p. 602 |
| Neoephemera bicolor | Imago - male genitalia | Needham p. 244 a |
| Neoephemera compressa | Larva - dorsal, half-grown | Berner - p. 80 fig. 156 |
| Neoephemera purpurea (Oreianthus purpureus) | Imago - fore & hind wing | Needham p. 290 |
| Neoephemera purpurea (Oreianthus purpureus) | Larva - dorsal | Needham p. 291 |
| Neoephemera youngi | Larva - dorsal, half-grown | Berner - p. 80 fig. 157 |
| Neoephemera youngi | Larva - dorsal view | Berner - p. 330 plate 20 |
| Neogerris | Imago - head & thorax dorsal | Merritt p. 281 fig. 15.77 |
| Neohaemonia | Imago - elytron | Merritt p. 457 fig. 20.303 |
| Neohermes | Imago - antenna basal male | Merritt p. 306 fig. 16.37 |
| Neohermes | Imago - fore & hind wings | Merritt p. 305 fig. 16.34 |
| Neohermes | Pupa - lateral view | Merritt p. 301 fig. 16.7 |
| Neohermes | Ova - egg mass | Merritt p. 302 fig. 16.15 |
| Neohermes concolor | Larva - segment VIII left spiracle dorsal | Merritt p. 303 fig. 16.25 |
| Neohermes filcornis | Larva - dorsal view | Merritt p. 302 fig. 16.22 |
| Neohermes filicornis | Larva - segment VIII left spiracle dorsal | Merritt p. 303 fig. 16.26 |
| Neopachylopus | Imago - antenna | Merritt p. 409 fig. 20.035 |
| Neophylax | Larva - thorax dorsal | McCafferty p. 263 fig. 14.70 |
| Neophylax | Imago - lateral view | LaFontaine p. 285 - b |
| Neophylax | Larva - case | LaFontaine p. 285 - a |
| Neophylax | Larva - case | Merritt p. 370 fig. 18.155 |
| Neophylax | larva - cased lateral | Pobst - p. 85-a |
| Neophylax | Larva - larva lateral & case | LaFontaine p. 286 |
| Neophylax | Larva - metathoracic claw | Merritt p. 367 fig. 18.138 |
| Neophylax | Larva - thorax dorsal | Merritt p. 369 fig. 18.141 |
| Neophylax | Larva - case | McCafferty p. 262 fig. 14.63 |
| Neophylax rickeri | Larva - head & thorax dorsal view | Bouchard p. 126 fig. 10.46 |
| Neophylax rickeri | Larva - lateral view | Bouchard p. 135 fig. 10.64 |
| Neoplea | Imago - fore tarsus | Merritt p. 283 fig. 15.99 |
| Neoplea striola | Imago - adult | McCafferty p. 174 fig. 10.05 |
| Neoplea striola | Imago - dorsal view | Bouchard p. 102 fig. 7.42 |
| Neoplea striola | Imago - lateral view | Bouchard p. 93 fig. 7.13 |
| Neoplea striola | Imago - lateral view | Merritt p. 283 fig. 15.96 |
| Neothremma | Larva - ab2 lateral | Merritt p. 383 fig. 18.265 |
| Neothremma | Pupa - abdomen dorsal | Merritt p. 328 fig. 17.86 |
| Neothremma | Pupa - ab8 & ab9 ventral | Merritt p. 328 fig. 17.85 |
| Neothremma | Larva - retreat | Merritt p. 311 fig. 17.14 |
| Neothremma | Larva - pronotum dorsal view | Merritt p. 383 fig. 18.267 |
| Neothremma | Imago - head, pro & mesonotum dorsal | Merritt p. 335 fig. 17.127 |
| Neothremma | Larva - head & thorax dorsal | Merritt p. 327 fig. 17.78 |
| Neothremma alicia | Larva - pro & mesathorax dorsal | Merritt p. 386 fig. 18.286 |
| Neotrichia | Larva - abdomen lateral | Merritt p. 363 fig. 18.89 |
| Neotrichia | Larva - case | Merritt p. 363 fig. 18.98 |
| Neotrichia | Larva - case | McCafferty p. 256 fig. 14.39 |
| Neotrichia | Larva - larva | McCafferty p. 256 fig. 14.38 |
| Nepa | Imago - abdomen ventral | Merritt p. 285 fig. 15.109 |
| Nepa | Imago - breathing tube dorsal | Merritt p. 285 fig. 15.111 |
| Nepa apiculata | Imago - adult | McCafferty p. 175 fig. 10.06 |
| Nerophilus californicus | Larva - ab1 ventral | Merritt p. 378 fig. 18.213 |
| Nerophilus californicus | Larva - thorax dorsal | Merritt p. 378 fig. 18.212 |
| Nerthra | Imago - foreleg | Merritt p. 279 fig. 15.60 |
| Nerthra | Imago - head & pronotum dorsal | Merritt p. 279 fig. 15.64 |
| Nerthra | Imago - head dorsal | Bouchard p. 92 fig. 7.11 |
| Nerthra martini | Imago - dorsal view | Merritt p. 279 fig. 15.63 |
| Neureclipsis | Larva - retreat | Merritt p. 311 fig. 17.02 |
| Neureclipsis | Larva - head & thorax lateral | Merritt p. 323 fig. 17.56 |
| Neureclipsis | Imago - lateral view | LaFontaine p. 300 - b |
| Neureclipsis | Larva - anal proleg & claw lateral | Merritt p. 381 fig. 18.244 |
| Neureclipsis | Larva - case | LaFontaine p. 300 - a |
| Nigronia | Imago - fore wing | Merritt p. 306 fig. 16.36 |
| Nigronia fasciatus | Imago - adult | McCafferty p. 194 fig. 11.06 |
| Nigronia fasciatus | Larva - segment VIII left spiracle dorsal | Merritt p. 303 fig. 16.28 |
| Nigronia serricornis | Larva - segment VIII dorsal | Merritt p. 302 fig. 16.21 |
| Nigronia serricornis | Larva - segment VIII left spiracle dorsal | Merritt p. 303 fig. 16.27 |
| Nixe | Imago - penes | Merritt p. 151 fig. 11.142 |
| Nixe | Larva - claw | Merritt p. 138 fig. 11.62 |
| Nixe horrida (Heptagenia horrida) | Imago - male genitalia | Needham p. 351 c |
| Nixe inconspicua (Heptagenia inconspicua) | Imago - male genitalia | Needham p. 352 c |
| Nixe kennedyi (Heptagenia kennedyi) | Imago - male genitalia | Needham p. 351 a |
| Nixe lucidipennis (Heptagenia lucidipennis) | Imago - male genitalia | Needham p. 352 d |
| Nixe perfida (Heptagenia perfida) | Imago - male genitalia | Needham p. 351 d |
| Nixe rusticalis (Heptagenia rusticalis) | Imago - male genitalia | Needham p. 352 b |
| Nixe spinosa (Heptagenia spinosa) | Imago - male genitalia | Needham p. 358 g |
| Notiodes (Endalus) | Imago - tarsus apical segs. lateral | Merritt p. 460 fig. 20.323 |
| Notiphila | Larva - abdomen posteolateral | McCafferty p. 326 fig. 16.90 |
| Notomicrus | Imago - fore leg | Merritt p. 428 fig. 20.107 |
| Notonecta undulata | Imago - adult | Schwiebert p.119-1 |
| Notonecta undulata | Larva - hind leg | Bouchard p. 93 fig. 7.16 |
| Notonecta undulata | Imago - adult | McCafferty p. CP IX fig. 049 |
| Notonecta unifasciata | Imago - dorsal view | Bouchard p. 93 fig. 7.15 |
| Notonecta unifasciata | Imago - dorsal view | Merritt p. 286 fig. 15.114 |
| Notonectidae | Imago - head lateral | Bouchard p. 43 fig. 3.32 |
| Notonectidae | Imago - lateral view | Bouchard p. 41 fig. 3.16 |
| Notonectinae | Imago - head | McCafferty p. 173 fig. 10.04 |
| Nyctiophylax | Larva - case | LaFontaine p. 302 |
| Nyctiophylax | Imago - lateral view | LaFontaine p. 301 - b |
| Nyctiophylax | Larva - case | LaFontaine p. 301 - a |
| Nymphula | Larva - lateral view | Bouchard p. 140 fig. 11.2 |
| Nymphulinae | Larva - dorsal view | Bouchard p. 140 fig. 11.1 |
| Nymphulinae | Larva - crochet | McCafferty p. 280 fig. 15.08 |