EXPLANATIONS OF TERMS USED IN TEXT.

281

mesothoracic episterna, (Figs. 30, 31).

mesothorax, the middle part of the thorax, to which the wing-covers andmiddle pair of legs are attached (Figs. 30, 31, 32).metamorphosis, changes an insect undergoes (Figs. 42, 43).metanotum, the upper or dorsal surface of the metathorax (Fig. 32).metasternum, the under surface of the metathorax (Fig. 30).metastethia, metathorax.

metathorax, the posterior part of the thorax, to which the wings andhind pair of legs are attached (Figs. 30, 31, 32).metastoma, tongue.metathoracic epimeron, (Fig. 30, 31).metathoracic episterna, (Fig. 30, 31).

metazona, the posterior part of the pronotum (Fig . on page 156).millimeter (mm.), the thousandth part of a meter, equal to 0.03937 inch,or nearly V 25 inch.

N.

nebulous, clouded; with uneven, cloudy markings.

nerves, the large ribs or veins of wing and wing-covers, extending from thebase towards the apex.

nerrules, the smaller connecting veins of the wings and wing-covers.nocturnal, active at night.

nymph, an immature insect active and feeding in the larval and pupalstage.

0 .

obconic, conical, with the vertex pointing downward.oblique, slanting.

oblong, with the transverse diameter much shorter than the longitudinal.obsolete, no longer functionally active.obtuse, obtusely, blunt.

ochraceous, brownish-yellow; of the color of ochre.ocelli, ocellus, the three simple eyes (Fig. 22).occiput, back part of head (Fig. 40).

oesophagus, passage for food to digestive tract (Figs. 40, 41).

omnivorous, eating everything eatable.

ootheca, a case enclosing eggs (Fig. 51).

opaque, without any lustre; impenetrable by light rays.

orifice, an opening.

oval, egg-shaped.

ovarioles,'one of the ovarian tubes or glands of which a composite ovariummay be composed.ovate, egg-shaped.

oviduct, the passage through which the eggs reach the outside.ovipositor, the organ for depositing eggs (Fig. 39),oviposition, the act of laying eggs (Fig. 3).