MOUTH PARTS. 



619 



FIG. 371. Mouth parts of a Blatta (alter Savigny). a H -nil 

 seen from the front ; Oc ocelli ; Mxt maxillary palp. Li labial 

 palp ; b upper lip (labrum, Lr.) ; c mandible (Md) ; d 1st 

 maxilla; C cardo ; St stipes ; L.in lacinia ; L. ex galea ; 

 e 2nd maxillae or labium (lower lip), clearly composed of 

 two halves. 



ptera and most 

 D i p t e r a. In 

 some may-flies 

 and caddis-flies 

 and Diptera, and 

 in the Macrolepi- 

 doptera t h e y 

 quite disappear 

 in the adult 

 stage. 



The append- 

 ages of the fifth 

 segment are, ac- 

 cording to Hey- 

 mons, the 1st 

 maxillae, and ac- 

 cording to Fol- 



som the maxiDulae. According to recent workers * a com- 

 plete and separate pair of gnathites succeed the mandibles in 

 the Apterygota (Collembola and Thysanura) which have been 

 variously termed paraglossae, superlinguae and maxillulae (Fig. 

 372). These maxillulae are reduced to the merest vestiges 



in the winged Insects (Pterygota). 



The first maxillae in the least specialized 

 cases consist of a segmented base (protopodite) 

 composed of two pieces, the proximal called 

 the cardo and the distal called the stipes. 

 The stipes ends in two lobes, the inner called 

 the lacinia, the outer the galea (Fig. 371). 

 At the junction of these with the stipes is 

 inserted on the outer edge, the segmented 

 palp, obviously a sensory and tactile organ. 

 Any of these parts may be much modified ; 

 thus in the Lepidoptera, the galea is elon- 

 gated and grooved and so united with its 

 fellow as to form a tube, through which the 

 liquid food is sucked, the lacinia and palp 



ff IG. 372. Right maxil- 

 lu'a of Machilis m-ni- 

 ti na x 72 (after Car- 

 penter). 1 lacinia; 

 2 galea ; 3 pa'p. 



* H. J. Hansen, Zool. Am., xvi. 1893, pp. 193 and 201. J. W. Folsom, 

 Bull. Mus. Comp. Zool., Harvard, xxxvi, 1900, p. 87. G. H. Carpenter, 

 P. Irish Ac., Ser. B, xxiv, 1903, p. 325. 



