Median shade or line: in Lepidoptera, crosses at or about middle of wings.

Median s.p.a.ce: in Lepidoptera, is the area between the median lines: in Odonata, the cubital cell (Comst.); the s.p.a.ce at base between submedian (radius) and postcosta (st a.n.a.l); 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.

Mediproboscis: the middle third of the flexed proboscis of muscid flies.

Medi-thorax: =mesothorax; q.v.

Medius: middle.

Mega- Megalo-: large.

Melanic: with a blackish suffusion.

Melanism: an abnormal or unusual darkening: a suffusion with blackish.

Mellifera: honey-makers: applied to bees as a whole.

Melliferous: honey-producing, or producers of honey.

Mellisugous: honey-sucking: a feeder on honey.

Member: any one of the external appendages.

Membranaceous: thin, skin-like, semi-transparent, like parchment: of a thin, pliable texture.

Membrana retinens: the stretched part of the membrane around the r.e.c.t.u.m of b.u.t.terfly larvae, used in the change to the chrysalis.

Membrane -ana: any thin, transparent, flexible body tissue: specifically the wing tissue between the veins: in Heteroptera, the thin membranous tip of the hemelytra.

Membranous or eous: composed of membrane or skin-like tissue.

Membranule: the small opaque expansion at base of wings in Odonata.

Meniscoidal: with one side concave the other convex, like a round segment from a hollow sphere.

Menognatha: insects in which both young and adults feed by mandibles; e.g. the Orthoptera: see menorhyncha and metagnatha.

Menorhyncha: forms in which both young and adult take food by suction e.g. Hemiptera: see metognatha and metagnatha.

Mental suture: in Coleoptera, the line between mentum and gula.

Mentigerous: bearing or having a mentum.

Mentum: a l.a.b.i.al sclerite bearing the movable parts; attached to and sometimes fused with the sub-mentum; corresponds to the (united) stipes of maxillae: in Coleoptera, what is usually called mentum is really submentum: in Diptera, the term is applied to the posterior oral margin: in Hymenoptera, is part of "tongue," the second joint bearing the l.a.b.i.al palpi, paraglossae and ligula.

Merdivorous: feeding upon dung or excrement: see scatophagous.

Meriaeum: the posterior inflected part of the metasternum in Coleoptera.

Meroistic: ovaries that secrete yolk or vitellaginous cells as well as ova.

Mesad: extending or directed toward the median plane.

Mesal: pertaining to, situated on or in the median plane of the body.

Mesenchym: that portion of the mesoderm that produces the connective tissues of the body.

Mesenteron: the mid-gut, stomach or chylific ventricle: the middle portion of the primitive intestinal ca.n.a.l, lined with entoderm.

Mesepimeron: in Odonata: the sclerite between humeral and first lateral suture.

Mesepisterna: in Odonata,- the oblique lateral pieces of mesothorax, meeting dorsally in a ridge.

Mesially: at or to the middle.

Mesinfraepisternum: a sclerite formed between propleuron, mesepisternum, mesepimeron and second c.o.xa.

Meso: middle: as prefix, drops the o when stem begins with a vowel.

Mesoblast: the middles germ layer of the embryos: = mesoderm.

Mesoderm:= mesoblast: gives rise to muscular and circulatory systems.

Mesodont::= amphiodont: q.v.

Mesomeros: the 2d to 5th abdominal segments in Lepidoptera.

Meson: the middle plane of the body.

Mesonotum: the primitively upper surface of the 2d or middle thoracic ring.