4 INTKOIHTCTIOX. 



calkul the hiisc, that noiiro.st the head is the ap.'.r, tlie cen- 

 tral portion of its surface is tlie disc. The scuteUum (a 

 trianguLir plate at the hase of the elytra (fiii;. 4,/) referred 

 to in descriptions is that of the niesonotuui, which part 

 also bears the horny anterior wings or wing cases (clf/tra). 

 The end of these nearest the thorax is called the hase 

 (fig. 4, ((), the other end the apex (fig. 4, h), the line in 

 which they meet one another along the back the nature 

 (fig. 4, c), their other side the outer side, or lateral margin 

 (fig. 4, d), and the central portion of their surface the 'disc 

 (fig. 4, c). The metanotum bears the membranous posterior 

 pair of wings used in flight. 



The under or sternal surface of each thoracic segment is 

 divided into tliree parts, the sternum (fig. 5, a), episterna 

 (fig. 5, />), and cpimera (fig. 5, c), the relative proportions of 

 wliicli are varial)le. The legs are attached to the body liy 

 means of a piece of various shape (partly eniljedded in a 

 socket hole or cotyloid cavity) called the coxa (fig. 5, d), a 

 short piece attarJuMl to tliis is the tivcJiantcr (fig. 5, e), the 



Klytra ol' Drwnuus 

 nigriventris. 



Uiulor-siilc of Protliiiiax of Caridiiis 

 iicinoralU. 



next piece is tlie femur (fig. 5, /), the next the tibia 

 (fig. 5, //), to whicli is attaclied the foot (tarsus, fig. 5, A), 

 composed of several joints, and bearing claws at the end. 

 The portion of each of these pieces nearest to the body is 

 the hase, and the other end the apex; the whole sternal 

 surface is sometimes called the breast. 



All the rest of the body forms the abdomen, consisting 

 of dorsal and ventral segments varying in number. On 

 the sides of these .segments lie the spiracles, thi'migli wliirh 



