500 
THE STUDY OF INSECTS . 
of the external wall of the head are frequently referred to in descrip¬ 
tions of beetles; these are the clypeus and the gula. The clypeus 
(clyp'e-us) is situated on the dorsal side of the head, and is the sclerite 
to which the labrum is attached. (Fig. 601, a , 5.) The gula (gu'la) 
is the central portion of the ventral wall of the head, and is the part 
which bears the labium (Fig. 601, b y 6). The sutures which bound the 
gula, one on each side, are termed the gular sutures (Fig. 601, b.gs). 
In the Rhynchophora the gula appears to be wanting, and there is a 
single suture on the middle line of the head (Fig.602, gs) ; in this case 
the gular sutures are said to be confluent. The suture which separates 
the clypeus from the sclerite immediately behind it (the epicranium) 
termed the clypeal suture (Fig. 601, a , cs). 
The Antenna. —The more common types of antennae are named 
and figured on page 60. But it is necessary to define two 
other terms here. In many insects the first segment of the 
antenna is long and the antenna is bent suddenly at the 
joint between the first and second segments; such antennae 
are said to be elbowed or geniculate (ge-nic'u-late). In some 
pectinate antennae the tooth-like processes are very long, 
giving the antenna a more or less fan-like appearance; such 
antennae arc defined as fiabellate (fla-bel'late) (Fig. 603). 
Fig. 603. The Mouth-parts .—The labrum and mandibles are suffi¬ 
ciently described on page 61. The parts of the maxillae are repre¬ 
sented in Figs. 604, 605, and 606; of these there are five primary 
parts and three appendages. The primary parts are the cardo or hinge 
(a), the stipes (sti'pes) or footstalk (<$), the palpifer (pal'pi-fer) or pal- 
pus-bearer (c), the subgalea (sub-ga'le-a) or helmet-bearer (e), and the 
lacinia (la-cin'i-a) or blade (g). The appendages are the maxillary 
palpus or feeler ( d ), the galea (ga'le-a) or outer lobe or superior lobe 
(/,/), and the digitus (dig'i-tus) or finger (h). 
