222 INDEX OF SCIENTIFIC TERMS 



Digitigrade — walking on the toes or claws. Cf. Plantigrade (q.v.) 46 

 Distal — part of limb or segment farthest from the centre of the body 



Ecdysis — ^moulting, casting of the outer skin in growth 



Endocuticle — inner layers of the integument 205 



Endite — endopodite (q.v.) 



Endopodite — inner ramus of a primitively forked arthropodan limb or 



mouth part 

 Endogenous rhythm — rhythm of activity that persists under constant 



conditions 24 

 Epicuticle — thin outermost chitin-free layer of the integument or cuticle 



xi, 205 

 Epigyne — external genitalia of the female Arachnid 

 Epimorphosis — development characteristic of centipedes in which slow 



growth takes place but the number of segments does not increase 57 

 Eury thermic — able to tolerate considerable variations in temperature. 



Cf. Stenothermic (5.^.) 190 

 Exocuticle — outer layers of chitinous endocuticle beneath epicuticle (q.v.) 



205 



Femur — third segment of an Arachnid's leg or palp 



Flagellum — a whip-like extension of the body, a limb or antenna. In 

 false-scorpions, a structure composed of setae on the chelicerae 



Galea — spinneret on movable finger in false-scorpions 104, 108 

 Genital operculum — chitinous plate covering reproductive opening 

 Geotaxis — directed movement in response to the stimulus of gravity 

 Gnathobase — projection from the coxa of a limb used to crush food 

 Gnathochilarium — mouth parts of millipedes composed of fused maxil- 

 lae 16,17,23,26,27,66 

 Gonopod — limb modified for sexual reproduction 19, 31, 37 

 Guanine — insoluble nitrogenous excretory compound characteristic of 

 Arachnids 206 



Haemocyanin — respiratory pigment found in Crustacea and Arachnids 

 in which the metallic element is copper and not iron as in haemoglobin 

 205 



Hypopus — resistant, dispersal stage of some mites 1 99-200 



Instar — larval, nymphal or other developmental stage of an arthropod. 



Instars change at moulting and metamorphosis (q.v.) 

 Ion — electrically charged atom or group of atoms 25 



Kinesis — non-directed locomotory response to a stimulus. Cf. Taxis (q.v.) 

 Kinetic reaction — kinesis (q.v.) 



