242 



THE VITAL FUNCTIONS. 



legs, the tail, and the antennae, the circulation is 

 carried on by means of vessels, which are con- 

 tinuous with the lateral vessels of the body ; 

 branching off from them in the form of loops, 

 ascending on one side, and then turning back to 

 form the descending vessel, so that the currents 

 in each move in contrary directions. Fig. 337 



represents the appearance of these parallel ves- 

 sels in one of the antennae of the Semhlis viridis, 

 magnified thirty times its natural size. The 

 whole system of circulating vessels in that in- 

 sect, of which the former is only a detached 

 part, is shown in Fig. 338, where the course 

 of the blood is indicated by arrows; a, repre- 

 senting the currents in the antennae ; w, those in 

 the rudimental wings ; and t, those in the tail ; 

 in all which parts the vessels form loops, derived 



