62 
THE STUDY OF INSECTS. 
appendages are termed the maxillary palpi. In the maxillae 
of certain biting insects, as the grasshoppers and the ground 
beetles, there is an appendage usually consisting of two 
segments: this is the galea (ga'le-a) or outer lobe. In some 
of these insects, as the ground-beetles and the tiger- 
beetles, the galea is shaped like a palpus, and thus there 
appears to be two pairs of maxillary palpi (Fig. 76). 
The labium is furnished with a pair of jointed appendages ; 
these are the labial palpi (Fig. 75, 12, d). 
The Thorax and its Appendages. 
The thorax is the second or intermediate region of the 
body ; it is the region that bears, in the adult insect, the 
organs of locomotion, the legs, and the wings when they are 
present. This region is composed of three of the body- 
segments more or less firmly joined together; the segments 
are most readily distinguished by the fact that each bears a 
pair of legs. In winged insects, the wings are borne by the 
second and third segments. The first segment of the thorax, 
the one next to the head, is named the prothorax; the 
second thoracic segment is the mesothorax; and the third, 
the metathorax. 
The Legs. —Each leg consists of the following parts, 
beginning with the one next to the body (see Fig. 77): 
coxa , trochanter , femur , tibia, 
and tarsus. Each of these 
parts consists of a single seg¬ 
ment except that in certain 
Hymenoptera the trochanter 
consists of two segments (Fig. 
77, /), and in most insects the 
tarsus consists of several seg¬ 
ments. The number of seg. 
ments of the tarsus varies from 
the most common number is five. Frequently 
the first segment of the tarsus is much longer than either of 
a b c 
Fig. 77.—Legs of insects : a. Wasp ; 5 , 
Ichne\imon-fly; c, Bee ; t, trochanter; 
in, metatarsus. 
one to six 
