VI 



ARTHROPODAN APPENDAGES 



227 



they form a miniature case of surgical instruments for piercing the skin 

 and obtaining a supply of blood ; in the Butterflies and Moths they 

 form a long tubular siphon which can be lowered into the depths of 

 deep flower corollas to suck up the nectar from their inmost recesses. 

 And yet a careful comparison of these various types of feeding equipment 

 show them to be composed of the same elements, the same series of 

 appendages, modified to varying extents in size and form so as efficiently 

 to perform their particular type of function. 



A relatively unspecialized set of insect mouth appendages is to be 

 found in the group Orthoptera, of which the Cockroach or " Black 



mx2 



mx\ 



FIG. 104. 



Mouth appendages of three different types of Insect. A, Cockroach (Periplaneta) ; B, Bumble- 

 Bee (Bombus) ; C, female Mosquito (Culex). c, Cardo ; g, glossae or ligula ; ga, galea ; h, hypo- 

 pharynx ; /, labrum ; Ic, lacinia ; l.p, labial palp ; m, mandible ; m.p, maxillary palp ; me, mentum ; 

 mx.i, first maxilla ; mx.2, second maxillae (labium) ; p.p, paraglossa ; s.me, submentum ; st, stipes.*" 



Beetle " is an example (Fig. 104, A). There are here three pairs 

 of such appendages the mandibles (m), the first maxillae (mx.i) 

 and the second maxillae (mx.2). Of these the mandible is simply a 

 gnathobase, ensheathed in very dense chitin with a sharp serrated inner 

 edge : there is no palp on the mandible in insects. The first maxilla is 

 much more complicated : its basal joint (cardo c} carries an elongated 

 piece (stipes st) and this in turn bears at its end two lobes, an inner, 

 claw-like and with stiff bristles the lacinia (Ic.), and an outer, soft and 

 cushion-like the galea (go). This appendage is provided on its outer 

 side with a jointed sensory maxillary palp (m.p). The second maxillae 

 can be seen to be composed of the same set of elements as the first 



