ANATOMY AND PHYSIOLOGY 12 
un 
ately under the integument. A simple tube in some larvee, it 
consists in most adults chiefly of a series of chambers, each of 
Fic. 159. 
HiGs 158. oP 
Diagram of a portion of the heart of a dragon 
fly nymph, Epitheca. o, ostium; v, valve; the ar- 
rows indicate the course of the blood. — After 
IXKOLBE. 
Fic. 160. 
Dorsal vessel of beetle, Diagrammatic cross section of pericardial 
Lucanus. a, aorta; al, alary region of a grasshopper, CEedipoda. a, alary 
muscle; o, ostium. — After muscle; d, dorsal vessel; s, suspensory mus- 
STRAUS-DURCKHEIM. cles; sp, septum.—After GRABER. 
Fic. 161. 
Blood corpuscles of a grasshopper, Stenobothrus. a-f, corpuscles covered with fat- 
globules; g, corpuscle after treatment with glycerine, showing nucleus.—After GRABER. 
which has on each side a valvular opening, or ostium (Fig. 
159), which permits the ingress of blood but opposes its egress ; 
