Microergates: the dwarf workers among ants.
Micron: the unit of microscopic measurement = 001 mm.: represented by the symbol µ: the symbol µµ represents .001 of a micron. { Scanner's note: the µµ notation would no longer be valid.}
Micropterism: the tendency to produce small wings; applied to a line of variation.
Micropyles: minute openings in the egg, through which spermatozoa enter.
Microsomites: small secondary rings or somites of the macrosomites in the embryo, which afterward become the body segments.
Microthorax: a supposed thoracic ring between the head and prothorax.
Middle apical area: = internal area; q.v.
Middle lobes: of pronotum in Orthoptera; see lobes.
Middle pleural area: in Hymenoptera; the median of the three areas between lateral and pleural carinae: = 2d pleural area.
Mid-dorsal thoracic Carina: a ridge or elevated line at the meeting of the mesepisterna in Odonata.
Mid-gut: the chylific ventricle with the caecal glands, tubes or pouches.
Migrants: applied to that brood of plant lice which flies from one to an alternate food plant: any forms that fly from the place where they were born for food or other purposes.
MM.: = Millimeter: .001 meter = .039 of an inch: roughly 25 mm. are counted to an inch in measuring insects. { Scanner's comment: modern usage is lower case. So: mm.}
Mimetic: when a species mimics or resembles another or some other object in appearance; but not in structure and other characters.
Mimicry: strictly, the resemblance of one animal to another not closely related animal, living in the same locality; often loosely used to denote also resemblance to plants and inanimate objects: Batesian mimicry is where one of two similar species is distasteful (so-called model), the other not distasteful (so-called mimic);
Müllerian mimicry is where both species are distasteful.
Mines: applied to galleries or burrows between upper and under surface of leaf tissue, when made by larvae: they are linear, when they are narrow and only a little winding; serpentine, when they are curved or coiled, becoming gradually larger to a head-like end: trumpet-mines, when they start small and enlarge rapidly at tip; blotch mines, when they are irregular blotches tentiform, when the blotch mines throw the leaf into a fold on one side.