Homoptera. 75 



11. Claval vein not reaching apex, united with commisural margin near apex; 



tegmina- sometimes shortened or fused with clavus and corium, when so, 

 the lateral margins of the clypeus are ridged; two or three ocellt. (Scolops, 



'^ Cixius) (PI. 15, figs. 366, 367) ClXim.^ 



Claval vein continued to the apex itself or united with the claval suture near 

 apex; tegmina sometimes shortened or fused with clavus and corium, when 

 so the lateral margins of the clypeus are not ridged 12 



12. First joint of hind tarsi elongate; head usually narrower than the thorax, 



which is angularly emarginate at base 13 



First joint of hind tarsi short, very rarely somewhat elongate; head not or 



scarce! jv -narrower than the thorax which is truncate at base.' (Brucho- ^- 

 morphaiNaso.) iSSID^<^ '^ 



13. Last joint of beak elongate; species of usual form, the wings not especially long. ^• 



(HeUcoptera.) ACHILID^ ^ 



Last joint of beak short, or very short; very delicate long-winged species. 

 ■ (Oti6cerus,%i6tia) (PI. 15. fig. 360) DERBID^ 



14. Tarsi two-jointed, the basal joint sometimes reduced, the outer joint with two 



claws; wings when present four in number, with few veins, at rest usually 

 lying in a sloping position over the abdomen; sutures between body seg- 

 ments distinct; mouth-parts usually well developed in both sexes, labium 



usually long 15 



Tarsi one-jointed, with a single claw; females always wingless, often without 

 legs so that they rarely move after maturity, remaining sessile on the host 

 plant; female rarely without mouth-parts; male usually with a single pair 

 of wings which lie flat, one above the other; labium usually short; antennae 

 of female absent, or with as many as eleven joints; in the male ten- to twenty- 

 five-jointed; body of female scale-like, gall-like or covered with waxy powder, 

 tufts or scales, the sutures between the segments often indistinct. Scale 

 Insects, Bark-lice, Mealy-bugs. (Orthezia, Kermes [Soft oak-scales], 

 Dactylopius [D. coccus, Cochineal-insect], Pseudococcus [Mealy-bugs], 

 Pulvinaria [P. vitis. Cottony-scale], Coccus [C. hcsperidum. Soft scale], 

 Evdecanium [E. nigrofasc.iatum, Terrapin scale], Chionaspis [C. furfura. 

 Scurfy scale], Aspidiotus [A. perniciosus, San Jose scale], Lepidosaphes 

 [L. ulmi {=Mytilaspis pomorum). Oyster-shell scale]) (PI. U'.^fig. 344, 

 346; PI. 15, figs. 362, 363, 364, 365) COCCIDiE 



15. Legs with thickened femora; antennse long, five- to ten-jointed, last joint with 



two fine apical bristles; fore wings somewhat thicker, often more or less 

 leathery; pad between the tarsal claws prominent, bilobed. Jumping 

 plant-lice. (Psylla [P. pyricola. Pear Psylla], Trioza) (PI. 16, fig. 368, 



371) {CHERMIDM) PSYLLID^ 



Legs long and slender; wings of more or less similar consistency; antennae 

 three- to six-jointed 16 



i6. Wings usually opaque, whitish, clouded, or mottled with spots or bands; body 

 more or less mealy; tarsi with two nearly equal joints; tip of tibiae with a 

 number of short spines; a pad-shaped or spine-like process between the 



