EXTERNAL ANATOMY OF INSECTS. 387 



flated, or very soft ; or concave plates, which cover 

 the underside, or their apex, of the four first joints 

 of the Manus or Tarsus, and sometimes even of the 

 ends of the Calcaria, as in Cimbex j which act so as 

 to produce a vacuum, and enable the animal to sus- 

 pend itself, or walk against gravity a . Ex. Timar- 

 cha, Bupreslis, Priocera K., the Gryllina, Musci- 

 dce, &c. 



III. ABDOMEN (the Abdomen). 



The Abdomen is the third or posterior section of the 

 body which follows the Truncus b . It includes the Ter- 

 gum, Venter, Petiolus, Cauda, and Anus. 



i. Tergum (the Tergum). The upper or supine surface 

 of the abdomen c . It includes the Segment a Dorsa- 

 lia, and Pulmonaria. 



1. Segmenta Dorsalia (the Dorsal Segments). Trans- 



verse segments of the back, the sides of which often 

 lap over and cover those of the ventral segments d . 



2. Pulmonaria (the Pulmonary Space). Two longitu- 



dinal soft spaces, capable of tension and relaxation, 

 one on each side of the back of the abdomen, in 

 which, where they exist, the dorsal spiracles are 

 planted e . They include the Spiracula Dorsalia. 

 a Spiracula Dorsalia (the Dorsal Spiracles). Late- 

 ral breathing-pores observable in the dorsal seg- 

 ments, often covered by the preceding segment f . 



* Plate XV. Fig. 9 ; and XXVII. Fig. 35, 59—61. f. 



h Plate VIII. Fig. 5, 6, 9, 15, 18, 19. 



c Ibid. Fig. 5, 15. A. d Ibid. A. 



e Ibid. Fig. 5, 9. B'. ' Ibid. Fig. 5, 9, 15. A'. 



2c 2 



