Cerci: The pair of lateral caudal filaments (tails), not including the central caudal filament (tail), when present.
Clypeus: Sclerites of the head between the frons and labrum.
Epicranial suture: Y-shaped articulation of plates on the dorsal surface of the head between the compound eyes.
Fibrilliform: Consisting of many thread-like structures
Fimbriate: Having a fringed margin.
Forceps: Elongate, paired reproductive strucures at the apex of the abdomen in male adults, lateral of the penes.
Frons: Portion of the dorsal surface of the head between the diverging arms of the epicranial suture.
Frontoclypeus: Portion of the head including the frons and clypeus.
Galea-lacinia: Mouthparts; fused galea at the tip of the maxilla, not including the palpus.
Glossa: Mouthparts; innermost paired lobes at the tip of the labium, between the paraglossa.
Habitus: General appearance and posture of the body.
Imago: Winged, adult mayfly. Last stage of development. Sexual stage. See Subimago.
Instar: A larval stage of development, between successive molts.
Labium: Most ventral mouthpoart, consisting of paired lobes and palpi.
Labrum: Most dorsal mouthpart, consisting of single flap-like structure.
Lamella: Thin and plate-like structure.
Macula: Mark or spot of coloration.
Mandibles: Paired chewing mouthparts ventral of labrum and dorsal of maxillae.
Maxillae: Paired mouthparts vnetral of mandibles and dorsal of labium.
Mesonotum: Dorsal sclerites of mesothorax.
Mesoscutum: Hardened exoskelital plates on the mesothorax.
Mesothorax: Middle thoracic segment, bearing the middle pair of legs and front wings or wingpads.
Mesosternum: Ventral sclerite of the mesothorax.
Metanotum: Dorsal sclerites of the posterior thoracic segment.
Metathorax: Posterior thoracic segment, bearign the hind pair of legs and hind wingpads (when the hind wingpads are present).
Naiad: Immature, aquatic life stage of mayflies and cerrtain other aquatic insect orders; used in older literature, but replaced with "larvae" in recent mayfly publications.
Notum: Dorsal sclerite of the thorax.
Nymph: Immature life stage of insects lacking complete metamorphosis, used in older literature but replaced with "larva" in reacent mayfly publications
Occiput: Posterior portion of dorsal surface of head capsule
Ocellus: Simple light-sensing organ on dorsal surface of head (pl.,ocelli).
Operculum: Lid or cover, as in gill covers of some mayflies
Osmobranchiae: Soft, finger-like extension of integument used for osmoregulation, as coxal bases of some mayflies.
Palmate: Pattern consisting of numerous branches radiating out form a central point.
Palpifer: Lobe of maxilla bearing a palpus
Palpus: Finger-like structures on lateral surface of maxilla or labium that is used for food handling.
Paraglossae: Lobes on labium located lateral to glossae and medial of labial palpi.
Parthenogenesis: Reproduction in which an unfertilized egg produces a viable embryo. Males of these species are rare or non-existant.
Pectinate: Comb-like structure.
Pedicel: Second segment of antenna, between scape and flegellum.
Penes: paired reproductive structures at apex of abdomen containing genital ducts in male adults; located between the forceps.
Pronotum: Dorsal sclerites of the prothorax.
Prosternum: Ventral sclerite of the prothorax.
Prostheca: Sclerite attached to median margin of mandible between incisors and molar region.
Psammophilous: Preferring sandy substrates.
Quadrate: Roughly rectangular.
Raptorial: Morphology suited for prey capture.
Scape: Basal segment of antenna
Sclerite: Hardened plate of exoskeleton.
Serrate: Having a saw-toothed edge.
Seta: (pl. Setae): bristle.
Spatulate: Spoon-shaped; flattened witih broad apex.
Spicule: Minute, unsocketed spine.
Subimago: Winged stage of development, unique to mayflies, occurring between larva and adult (imago).
Tarsus: Distal region of leg, bearing one or more claws at apex.
Tergum: Dorsal surface of abdomen.
Tibia: Forth segment of leg, between femur and tarsus.
Trachea: Tube of the respiratory system, including any within gills.
Trochanter: Second segment of leg, between coxa and femur.
Villipore: Patch of short setae near proximal end of ventral surface of femur in some specimens.
Mayflies Terms