. A manual for the study of insects. Insects. COLEOPTERA. 501 The parts of the maxilla to which reference is most often made are the palpus and the galea. The number and form of the segments of the palpus are much, used in descriptions; as is also the presence or absence of the galea. When the galea is developed as-a distinct ap- pendage, the maxilla is said to be bilobed, the galea being termed the outer lobe, and the lacinia, or blade, the inner lobe (Fig. 604). When the galea is not developed so as to appear as an appendage the maxilla is said to have but one lobe. Much use is made of the f
. A manual for the study of insects. Insects. COLEOPTERA. 501 The parts of the maxilla to which reference is most often made are the palpus and the galea. The number and form of the segments of the palpus are much, used in descriptions; as is also the presence or absence of the galea. When the galea is developed as-a distinct ap- pendage, the maxilla is said to be bilobed, the galea being termed the outer lobe, and the lacinia, or blade, the inner lobe (Fig. 604). When the galea is not developed so as to appear as an appendage the maxilla is said to have but one lobe. Much use is made of the form of the parts of the labium or lower lip in descriptions of beetles. When fully developed the labium con- sists of three principal parts and a pair of appendages. The principal parts are the submentum, the mentum, and the ligula ; the appendages are the labial palpi. The basal part of the labium, the part which is joined to the gula, is the submentuin (Fig. 607, sin). By an unfortunate error this sclerite is almost in- variably described in works on the Coleoptera as the mentum. This fact should be borne in mind by the student when using any of the older books on this subiect. The intermediate portion of the labium is ^^g- 607. — Labium •' * , . of Creophzius: sm^ the mentwn (Fig. 607, m); and the distal portion submentum;/«, 1 ,. T rr-i 1' 1 • J i_ ^ mentum; jc, labial the ligula. The ligula is a compound organ ; but palpus; g-, giossa, in beetles the sutures between the different sclerites ^' paragiossa. of which it is composed are usually obsolete. Three parts, however, are commonly distinguished, a central part, which is sometimes divided at the tip, th^glossa (Fig. 607,^), and two parts, one on each side of the glossa, iht paraglosscB (Fig. 607, p). The part on each side which bear the palpus is termed, when it is distinct, The Thorax.—Each segment of the thorax is composed of several sclerities. The shape and relative position of these sclerites
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectinsects, bookyear1895
