THE INSECTA 



153 



maxilla, and an inner moiety corresponding to the lacinia. 

 The exopodites or palps of the second maxillae are three- 

 jointed. 



A shield-shaped aperture, called the occipital foramen, marks 



Fig. 37 



A. Right mandible of Periplaneta orientalis. B. Right maxilla, ca, 

 cardo ; st, stipes ; la, lacinia ; gal, galea ; /./, palp. C. The labiuin 

 seen from behind, sin, sub-mentum ; m, inentum ; ga, paraglossa, 

 corresponding to the galea of the maxilla ; la, lacinia ; /./, palp. 

 D. The mesothoracic limb of the right side, ex, coxa; tr, tro- 

 chanter \fe, femur ; tb, tibia ; ta, the five-jointed tarsus. The limb 

 is drawn to a smaller scale than the mouth parts. 



the place where the neck joins the back of the head. The 

 neck itself is slender and soft, covered with a soft white cuticle 

 except for seven hard chitinous patches or sclerites, of which 

 one is dorsal, two ventral, and two pairs lateral. 



The three segments of the thorax are known as the 



