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 field: = discoidal field; 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.
Mid-intestine: = mid-gut.
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.