viii Explanation of Terms. 



Cornea. — The horny convex covering of the eye. 



Cora.— The basal joint of the leg. {PL W.fig. 6, a.) 



Cuticle. — The thin outer skin of the leaves and other parts of a plant. 



Depressed. — Flattened from above downwards, as opposed to ' compressed 



(which see;. 

 Diagnosis. — A short distinctive description by which the genus, species, &c., 



of the insect may be recognised. 

 Z>z^//«/^^.— Appendages frequently present on the feet of Coccidae, either broad 



and spatulate, or in the form of knobbed hairs. {PL II. fg. 6, g, k.) 

 Dimerous. — Composed of two pieces. 



Dorsad. — Towards the 'dorsum.' (A term of comparative direction.) 

 Z>^rja/.— Relating to the back or upper parts of the body. 

 Dorsal scale. — The part of the covering scale (puparium) of the DiaspincE that 



lies above the insect, as opposed to the ' ventral scale ' which completes 



the puparium below. 

 Dorsum. — The back or upper parts of the body. 

 Eccentric. — Away from the centre. Out of centre. 

 Ecdysis. — The periodical ' moult ' or change of skin. 

 Emarginate. — Having a notch as if a piece had been cut out. 

 ExuvicB. — The discarded skins shed at the periodical moults (ecdyses). 

 Femur. — The thigh or upper part of the leg, situate between the * trochanter ' 



and the 'tibia.' (For purposes of measurement, the 'trochanter' and 



'femur,' being fused together, are considered as one piece.) {PL II. 



fig. 6, c) 

 Filiform. — Thread-like. 



Fimbriate, fimbriated.— Ynngtdi. With finely divided margin. 

 Function. — The action or operation of any ' organ ' (which see). 

 Funicle. — The long terminal joint of the antennse of larval Diaspinc^. 

 Gence. — The cheeks. The sides of the head behind the eyes, {PL U.fig. 4, c.) 

 Genital spike. — The sheath of the penis, which in the males of Diaspince takes 



the form of a long mucronate spike. {PL W.fig. lo.) 

 Gestation. — The period during which the gravid female is maturing the ova or 



embryos. 

 Grouped glafuis. — (See ' Circumgenital glands.') 

 Halteres. — A pair of small organs (sometimes called ' Balancers ') which replace 



the hind wings in the males of Coccidse and the two-winged flies (Diptera). 



(In the Coccidse they take the form of a strap-shaped basal part, with 



one or more longish, stout-hooked bristles on the extremity.) {PL II. 



fig- 3-) 

 Ho?nologous. — An organ or any part of an animal is said to be ' homologous ' 



with another part when the two have the same origin — without of 



necessity having the same function. (As opposed to ' analogous,' in 



which the two parts have a similar function, although with a different 



origin.) 

 Honey-dew. — A sweet, viscid substance excreted by Coccidas and some other 



homopterous insects. 

 Incised. — With marginal slits or notches. 

 Laterad. — Towards the side. (As indicating the position of one part in relation 



to another.) 



