ANATOMY AND PHYSIOLOGY 39 
maxilla consists of three lobes, namely, palpus, galea and 
lacinia, which are borne by a stipes, and hinged to the skull 
by means of a cardo. The palpus, always lateral in position, 
is usually four- or five-jointed and is tactile, olfactory or gus- 
tatory in function. The lacinia is commonly provided with 
teeth or spines. The maxillz supplement the mandibles by 
holding the food when the latter open, and help to comminute 
the food. Additional maxillary sclerites, of minor impor- 
tance, often occur. 
The labium, or under lip, may properly be likened to a united 
pair of maxille, for both are formed on the same three-lobed 
plan. This correspondence 1s evident 
in the cockroach, among other gener- 
alized insects. Thus, in this insect 
(Fig. 44) : 
LaBiuM = MAXILL= 
palpus = palpus 
paraglossa= galea 
glossa = lacinia 
palpiger = palpifer 
mentum = stipites 
submentum with gula= cardines 
In most mandibulate orders the 
glossz unite to form a single median 
3 ; Labium of Harpalus caligi- 
organ, as in Harpalus (Fig. 47, g).  nosus, ventral aspect. g, 
united glosse, termed the 
glossa; m, mentum; p, palpus; 
pharynx and assists 10 carrying food bg, palpiger; pr, paraglossa; 
= a sm, submentum. The median 
to the mandibles and maxille. portion of the labium beyond 
iihiewuses or the term 
The labium forms the floor of the 
the mentum is termed the 
ligula 
oe 
second 
) 
maxille” for the labium of an $in- 
sect is open to objection, as it implies an equivalence with 
the second maxillze of Crustacea 
established. 
which is by no means 
The tongue, or hypopharynx, is a median fleshy organ (Fig. 
44) which is usually united more or less with the base of the 
labium. In insects in general, the salivary glands open at the 
