THE INTERNAL ANATOMY OF INSECTS 



151 



the front trachea (Ti) and the hind trachea (Te); these two branches 

 reunite a short distance beyond the end of the chordotonal organs. 



It is an interesting 

 fact that these large 

 tracheae of the legs 

 containing the chor- 

 dotonal organs open 

 through a pair of 

 supernumery / s p i r - 

 acles, differing in this 

 respect from the tra- 

 cheae of the other legs. 

 The spaces of the 

 leg. - By reference 

 to Figure 172, it will 

 be seen that the two 

 branches of the leg 

 trachea occupy the" 

 middle space of the 

 leg between the two 

 tympana (Tie and 

 Tii) and separate an 

 outer space, the upper 

 one in the figure, from 

 an inner space. The 

 outer space (E) con- 

 tains a chordotonal 

 organ, of which the 

 scolopale is repre- 

 sented at S; and the 

 inner space contains 

 small tracheae (t), 

 muscles (m), the 

 tibial nerve (Xtb;. 

 and a tendon iTn). 



Fig. 1 7 1. -Longitudinal . section of a fore tibia of The in terstices of the 

 Decticns verrucivorus (From Berlese after Schwa 1 outer andinner spaces 



are filled with blood. 



In the outer space some leucocytes and fat-cells (Gr) are represented. 



The supra-tympanal or subgenual organ. In the outer space of 



the tibia, a short distance above the tympana, there is a ganglion (Fig. 



