Principal British Insects : — Termi?tologi/, 



423 



grub or caterpillar state, and a few undergo no material change 

 whatever, after they are hatched from their egg or embryo. 



Insects, in their imago or perfect state, are composed of 

 four principal parts: viz. caput, the head; truncus, the trunk ; 

 abdomen, the hinder part ; and artus, the members. 



Caput, the head {Jig' 180. «), is furnished with 6culi> eyes (b), 

 180 ,e , in number 



from two to 

 eight ; anten- 

 nae, horns (c) ; 

 OS, the mouth 

 (d), composed 

 of labrum su- 

 ^/jperius, the up- 

 per lip, and 

 labrum inf^- 

 rius, the lower 



lip ; mandibulae, mandibles or lateral jaws (e) ; maxillae, 

 lateral appendices of the mouth {/) ; galeae, shields of the 

 mouth ; ligula, a latchet, acting as a lower lip, situated under 

 the jaws ; lingua, the tongue ; rostrum, a movable l>eak ; pro- 

 boscis, the feeding trunk; haustellum, the mouth of some 

 insects, so called from its property of drawing up and folding 

 under ; palpi, feelers ; frons, the face ; clypeus, the shield of 

 the head; vertex, the crown of the head; and gula, the 

 throat (g), 



Truncus, the trunk, consists of the th6rax, the part between 

 the head and the base of the wings (k) ; pectus, the breast (i), 

 to which the legs are attached, as also, 

 in some cases, the wings and elytra ; 

 sternum, the breast-bone {k) ; and 

 scutellum, a little shield, situate at 

 the posterior part of the thorax (/). 



To the trunk are also attached alae, " ' " isi 



the wings ; elytra, the wing-covers (m) ; and halteres, the ba- 

 lancers, exemplified in the common house-fly, and in Zipula. 

 (Jig 181. a a). 



Abdomen, the belly or third principal division, contains the 

 intestines, ovary {^g. 180. n), &c. ; and consists of the tergum, 

 or upper part ; venter, the belly ; cauda, the tail ; and aculeus, 

 the sting. 



Artus, the members, are pedes, the legs : composed of 

 coxa, the first joint (o) ; femur, the thigh {p) ; tibia, the 

 shank {q) ; tarsus, the foot (r) ; and unguis, the claw [s). 



All these parts differ in form, colour, and consistence, as will 

 appear in describing insects of the different orders. These 



