_Haltere._ A minute organ, situated just behind the wings of the males, and of which the use, either in this family or in the Diptera, has not been satisfactorily ascertained. It is often termed the "balancer." In the house-fly it has been thought to represent an organ of hearing. In Coccids it is furnished with one or more hooked bristles, and Mr. Comstock affirms that these are, probably for some purposes of flight, hooked into the posterior edges of the wings.[A] (Plate i., Fig. 17; Plate xxi., Fig. 1, _m_.) [A] Report of the Entomologist, U.S. Dep. of Agric. 1880, p. 277, note. _Honeydew._ A substance of a glutinous character produced by many species, and falling in spray from them on the leaves. (See Chap. III.) _Larva._ The first stage in the insect's life after emerging from the egg. _Lobes_, in the _Diaspidinæ_, are minute, flat, more or less rounded projections, two or more, seen on the edge of the abdominal extremity, usually interspersed with spines and hairs (Plate iii., Figs. 1, 3, 4, 5, _l_); in the _Lecanidinæ_, are two triangular or conical projections, usually bearing hairs, on the dorsal side of the body, one on each side of the abdominal cleft (Plate xi., Fig. 3, _b_, _c_). _Mentum._ A kind of secondary rostrum, or "under-lip," not altogether tubular, but rather a deepish trough, through which the rostral setæ pass after leaving the rostrum. It may have one, two, or three joints. It is not noticeable in the Diaspidinæ. (Plate i., Fig. 5, _b_.) _Metamorphosis._ A change of form. For the number and characters of these see Chap. II. _Moniliform._ Like a string of beads. _Monomerous._ With a single joint. _Multilocular._ With several divisions: a term applied to the spinneret orifices of some insects, distinguishing them from "simple" orifices, which show only a single tube. Multilocular orifices exhibit a bundle of tubes enclosed together. (Plate i., Fig. 4, _c_, _d_, _p_; Plate xviii., Fig. 2, _e_.) _Nervure._ A strong vein which, starting from the attachment of the wing of the male, runs along the anterior edge of the wing, a little within it: at about half its length a branch runs obliquely towards the posterior edge. (Plate i., 16; Plate xix., _f_; Plate xxi.) _Normal._ According to rule--not exceptional. _Ocelli._ Two, four, or six minute circular simple organs, on the head of the male: probably organs of vision. In the _Monophlebidæ_ they would seem to be replaced by a smooth rounded protuberance behind the eye. (Plate i., Fig. 14, _oc._; Plate viii., Fig. 2, _k_, _m_; Plate xxi., Fig. 2, _b_.)