42 EXPLANATION OF TERMS 



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 ento- 

 trophous. 



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. 



Eflected: 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 shell 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 vagina. 



Egg-case: the case or covering prepared or secreted by an insect to contain 

 or hold together the egg-mass as a whole : see ootheca. 



Egg-guide: Orthoptera; two small pointed prolongations of the ventral por- 

 tion of the 8th abdominal segment, between upper and lower valves, used 

 in oviposition. 



Egg-pouch: see ootheca. 



Egg-pod: applied to the egg-mass of grasshoppers. 



Egg-tube: see ovarian tube. 



Ejaculatory duct: see ductus ejaculatorius. 



Elastic: a part which has a degree of flexibility throughout. 



Elate -us: see elevatus. 



Elater: the spring or forked tail of Podurids. 



Eleutherata: all forms with free, separated maxillae; later, and more spe- 

 cifically, the Coleoptera. 



Elevate -us: a part higher than its surroundings. 



Elinguata: without a tongue: forms in which the maxillae are connate with 

 the labium : see synista. 



Ellipsoidal: see elliptical. 



Elliptical: oblong-oval, the ends equally rounded, together forming an even 

 ellipsoid. 



Elongata -ate : drawn out ; lengthened ; much longer than wide. 



Elutus: with scarcely distinct markings. 



Elytra: the anterior leathery or chitinous wings of beetles, serving as cover- 

 ings to the secondaries, commonly meeting in a straight line down the 

 middle of dorsum in repose : also applied to the tegmina in Orthoptera. 



Elytral ligula: a tongue-like process on the inner face of the side margin of 

 elytra, to perfect the union with the ventral segments : e. g., in Dytiscidce. 



Elytriform: shaped or appearing like an elytron. 



