Dorso-alar region: Diptera; between the transverse suture and the scutellum on one side and the root of the wing and the dorso-central region on the other.

Dorso-central bristles: Diptera; two or four longitudinal rows on the inner part of the dorsal.

Dorso-central region: Diptera; bounded by two imaginary lines drawn from the scutellar bridges forward, and coinciding with a s.p.a.ce free from bristles that exists on the outer side of the dorsal rows and is often occupied by a dorsal thoracic stripe.

Dorso-humeral region: Diptera; bounded by the anterior end of thorax and transverse suture on two sides and by the dorsopleural suture and dorsocentral region on the two others.

Dorsolum: the mesoscutum.

Dorsopleural suture: Diptera; the lateral suture between dorsal and pleurum from the humeri through the base of the wing: separates the mesonotum from the pleura.

Dorso-ventral: in a line from the upper to the lower surface.

Dorsulum: the mesonotum before the scutellum, with the wing sockets: also, specifically, the meso-scutellum.

Dorsum: the upper surface: in Coleoptera; often confined to meso- and meta-thorax: Odonata; includes mesepisterna and meso- and meta-thoracic terga: Diptera; upper surface of thorax, limited by the dorsopleural sutures laterally, the scutellum posteriorly and the neck anteriorly: Lepidoptera; the lower or inner margin of the wing.

Draw-thread: the silk-producing gland.

Drone: in Hymenoptera; the male bee.

Duct: a channel, tube or ca.n.a.l for carrying a secretion from a gland to the point of discharge.

Ductus ejaculatorius: the single duct or tube formed by the union of the vasa deferentia from each side, through which the seminal fluid is ejected into the v.a.g.i.n.a.

Dufour's gland: that gland, in Hymenoptera, that secretes the alkaline portion of the poison carried by the sting.

Duodenum: the chylific ventricle; also applied to the first section of the digestive tract just behind entrance of malpighian tubules.

Dupion: a coc.o.o.n spun by two silk-worms together; also the coa.r.s.e silk from such a coc.o.o.n.

Duplicate -us: double.

Duplicate-pectinate: having the branches of a bipectinated antenna alternately long and short.

Duple: double, or twice.

Durus: hard.

Dusky: somewhat darkened; pale fuscous.

E

E: as prefix, is privative and means without.

Ears: organs of hearing, as on the first tibiae or on the first abdominal segment of some Trichoptera.

Ebenine: black like ebony.

Eburneous: ivory white.

Ecalcaratus: without a spur.

Ecaudate: without tails or tail-like processes: usually applied to wings : = excaudate.

Ecdysis: the process of casting the skin; moulting.

Echinate: set with p.r.i.c.kles.

Ecology: the science of the relation of organisms to each other and to their surroundings: = ethology. {Scanner's comment: Ethology nowadays refers to studies in animal behaviour, not directly to ecology.}

Ectad: extending outwardly from within.

Ectal: belonging or relating to the outer surface.

Ectoblast: the outer wall of a cell; the ectoderm or epiblast.

Ectoderm: the outer layer of skin: the outer layer of the blastoderm, giving rise to the nervous system and to epithelial structures of the body surface.

Ectognathus: see ectotrophous.

Ectoskeletal: referring to the outside or exoskeleton.

Ectotrachea: the outer surface or layer of the trachea.

Ectotrophous: with mouth parts free; not buried in the head: see entrotrophus.

Edematus: dull translucent white.

Edentate -ulous: without teeth.

Edentula: those having no teeth.

Efferent: carrying outward or away from the centre.

Effluvium: a foul or unpleasant smell or emanation.

Effected: somewhat angularly bent outward.

Egg: a simple cell, capable of fertilization, containing the germ, the food-yolk necessary for its nutriment, and a covering membrane: a single ovum or cell from an ovary: the first stage of the insect.

Egg-burster: a projecting point on the head or other part of an embryo, used in breaking the sh.e.l.l when hatching.

Egg-calyx: the enlarged portion of the oviduct at the opening of the ovarian tubes, into which the egg is received before its entrance into the v.a.g.i.n.a.