Median segment: applied to the basal segment of the abdomen when it forms part of the metathorax: see propodeum.
Median shade or line: in Lepidoptera, crosses at or about middle of wings.
Median space: in Lepidoptera, is the area between the median lines: in Odonata, the cubital cell (Comst.); the space at base between submedian (radius) and postcosta (st anal); by Selys in 1896 and later used in the sense of medial cell of Comst.
Median vein: in Odonata and Lepidoptera, = radius (Comst.): in Lepidoptera, it runs from base to about middle, nearly through centre, and is four or five branched: in Hymenoptera, it is the 3d from costal margin.
Mediastinal: relating to the longitudinal median line or area.
Mediastinal area: in Orthoptera, the area between median or mediastinal vein and the costal or front margin: = marginal area.
Mediastinal vein: in Orthoptera and Diptera, = suhcosta (Comst.): also, in Diptera, = auxiliary vein (Meigen).
Medio-eubital cross-vein: between media 4 and cubitus, connecting the two series (Comst.).
Medio-ventral line: in caterpillars, extends along middle of under side.
Medipectus: the under side of meta-thorax: the mesosternum.