22 



WILLIAM T. M. FORBES 



Each maxilla (save in Epimartyria ) consists mainly of a slender, 

 coiled portion, the galca (figs. 37, 49). The base of the maxilla in 

 many cases bears a two- to four-jointed sensory organ on the outer 

 side, the maxillary palpus. The two maxilla? are grooved on their 

 inner sides and hooked together to form a hollow sucking tube. 

 Together they are known as the tongue. 



The tongue may vary in size and stiffness. When it is shorter than 

 the head in slender moths, or shorter than the thorax in heavy and 

 strong ones, it is considered rudimentary in systematic work, as it is 

 in the Pyralids if it is not large enough to show between the palpi 

 when coiled up. It has sensory bristles at the tip and often bears 

 scales at the base, but as a rule the base is naked. In certain noctuids, 

 as Alabama argillacca, the bristles at the tip form a rasping organ 

 with which the rinds of fruits can be pierced. A few moths lack the 

 tongue. The maxillary palpi are conspicuous and five-jointed in the 

 lowest moths, and are folded at rest, being more or less movable. As 

 one goes up the scale they become smaller, till in our Noctuidge they 

 are mere microscopic, scaly tufts, and in the butterflies and the Greo- 

 metridae they are unrecognizable. 



The labial palpi, often called merely the palpi, arise on each side 

 behind the base of the tongue (in the lower forms from a small labium, 



'6 



FlO. 10. LATERAL VIEW OF THORAX, DENUDED, WITH WINGS AND LEGS BEHOVED 



Al, alula of hind wing; B, entrance to tympanic bulla; Cx, coxa; Epm, epimeron; 

 Eps, episternum; M, meron; n. scl.. nodular sclerite of tympanum; 2P, 3P, paraptera 

 (3P is the "subalar sclerite"); psc, prescutum; scl, scutellum; set, scutum (sctj 

 is the patagium) ; ISp, spiracle of first segment of abdomen] S, sternum (thorax) ; 

 ISt, sternite of iirst segment of abdomen; Tg, tegula; tgA, tegular arm; tpl, tergo- 

 pleural groove; Tymp, membrane of tympanum; Wp, wing process of pleurites; (The 

 subscript numbers, 1, 2, 3, indicate the segments of the thorax) 



