TERZI  . -_ . After

Howard, Year Book U.S . Dept . Agr., 1894 . into a process or hood-like structure which may extend far behind the tail-end of the abdomen . Two other allied families, the Cercopidae and Jassidae, are more numerously represented in our islands . The young of many of these insects are green and soft-skinned, protecting themselves by the well-known frothy secretion that is called " cuckoo-spit." In all the above-mentioned families of Homoptera there are three segments in each foot . The remaining four families have feet with only two seg- Pmm Osborn (after Deane), meets. hey are of B:dl . 5 (N.S.), Div . Ent. very great zoological G.S . Dept .

Agr.

interest on account of ( Pediculus vestimenti). their life-history—par- Magnified. thenogenesis being of normal occurrence among most of them . The families Psyllidae or " jumpers ") with eight or ten segments in the feeler and the Aleyrodidae (or " snowy flies ") distinguished by their white mealy wings, are of comparatively slight importance . The two families to which special attention has been paid are the Aphidae or plant-lice (" green fly ") and the Coccidae or scale-insects . The aphids (fig . II) have feelers with seven or fewer distinct segments, and the fifth abdominal From Osborn (after segment usually carries a pair of tubular pro- Schiodte), Ball., (IV .S.), cesses through which a waxy secretion is dis- Div . Ent . U.S . Dept. charged . Tha sweet " honey-dew," often Agr . . sought as a food by ants, is secreted from the FIG . 15 . — Pro-intestines of aphids .

The

peculiar life-cycle in boscis of Pediculus. which successive generations are produced Highly magnified. through the summer months by virgin females —the egg developing within the body of the mother—is de-scribed at length in the articles APHIDES and PHYLLOXERA . The Coccidae have only a single claw to the foot; the males (fig . 12 a) have the fore-wings developed and the hind-wings greatly reduced, while in the female wings are totally absent and the body undergoes marked degradation (figs . 12, e, 13, a, b) . In the Coccids the forma- tion of a protective waxy secretion—present in many genera of Homoptera—reaches its most extreme development. in some coccids —the " mealy-bugs " (Dactylopius, &c.) for example—the secretion forms a white thread-like or plate-like covering which the insect carries about . But in most members of the family, the secretion, united with cast cuticles and excrement, forms a firm " scale," closely attached by its edges to the surface of the plant on which the insect lives, and serving as a shield beneath which the female coccid, with her eggs (fig . 13 a' and brood, finds shelter . The male coccid passes through a passive stage (fig . 4) before attaining the perfect condition . Many scale-insects are among the most serious of pests, but various species have been utilized by man for the production of wax (lac) and red dye (cochineal) . See ECONOMIC ENTOMOLOGY, SCALE-INSECT . ANOPLURA The Anoplura or lice (see LOUSE) are wingless parasitic insects (fig .

14) forming an

order distinct from the Hemiptera, their sucking and piercing mouth-organs being apparently formed on quite a different plan from those of the Heteroptera and Homoptera . In front of the head is a short tube armed with strong recurved hooks which can be fixed into the skin of the host, and from the tube an elongate more slender tucking-trunk can be protruded (fig . 15) . Each foot is provided with a single strong claw which, opposed to a process on the shin, serves to grasp a hair of the host, all the lice being parasites on different mammals . Although G . Enderlein has recently shown that the jaws of the Hemiptera can be recognized in a reduced condition in connexion with the louse's proboscis, the modification is so excessive that the group certainly deserves ordinal separation .