GENERAL CHARACTERISTICS. 
7 
externally the jointed palpi, resembling those of the maxillas, and between these 
there is a median, sometimes bilobed, piece, called the ligula, and a pair of pieces 
termed the paraglossge. The degree of development of the several parts varies 
greatly in different orders, and it is often a matter of considerable difficulty to 
determine the exact correspondence that exists between them in two insects 
belonging to different orders. This is especially the case when the jaws have 
been modified to form the different organs of suction that are met with. The 
structure of these will be described in detail when the species that possess them 
are discussed. Another organ to be mentioned in connection with the jaws is a 
(Andrena) ; 4, Maxilloe and labium of saw-fly ( Cimbex ); 5, Lower view of head of carnivorous beetle 
( Procrustes ); 6, Maxilla of carnivorous beetle (Cicindela) ; 7, Maxilla of cock-tail beetle (Staphylinus); 8, 
Maxilla of locust; 9, Head of bug (Cicada) from the front; 10, Head of butterfly; 11, Head of horse-fly 
( Tachina ). 
Labium — a, mentum ; b, ligula; b', paraglossse ; c, palp ; d, mandible. Maxilla (e), with/cardo ; g, stipes ; 
h, lacinia; h', galea; i, palp ; k, head-plate ; n, teeth on laciuia. 
membranous lobe, called the liypopharynx, or tongue, projecting into the interior 
of the mouth from the floor of the labium. 
The thorax, or median part of the insect’s body, is formed of three segments 
called the pro- meso- and metathorax, each of which is composed of several distinct 
pieces. The dorsal areas of the three segments are termed the pronotum, meso- 
notum, and metanotum; the lateral regions the pleurie; and the inferior regions 
the sterna. To the pleurge are articulated the three pairs of legs, each of which 
consists primarily of five segments, named respectively, from the base to the apex, 
coxa, trochanter, femur, tibia, and tarsus; the last, which constitutes the foot, being 
generally tipped with two claws, and subdivided into several often as many as 
five—smaller segments. To the sides of the upper surface of both the meso- 
