Mouthparts of Cloeon dipterum (Linnaeus, 1761) measured with their acronyms. a Head, dorsal view. b Labrum. c Right mandible, d Left mandible. e Hypopharynx. f Right maxilla. g Left maxilla. h Labium. hw: head width; hl: head long; lw: labrum width; ll: labrum long; rmdw: right mandible width; rmdl: right mandible long; lmdw: left mandible width; lmdl: left mandible long; hsw: hypopharynx superlingua width; hsl: hypopharynx superlingua long; liw: lingua width; lil: lingua long; mpw: maxillary palp width; mpl: maxillary palp long; gw: glossae width; gl: glossae long; pw: paraglossae width; pl: paraglossae long; lpw: labial palp width; lpl: labial palp long. The blue arrows indicate the articulatory surfaces.