PARACOROTOCA AKlilRMANl (waRRHN). 325' 



distribution of the tracheal tubes has been made. The 

 arrangement of the spiracles has already been indicated. 

 There is a large spiracle immediately behind the prosternal 

 epimeron and generally regarded as prothoracic. No clearly 

 defined mesothoracic spiracle could be found, but a metJi- 

 thoracic one (PI. XA^I, fig. 1) is present, being phiced rather 

 posteriorly and latei-o-dorsally. Abdominal spiracles, not 

 sensibly smaller than the thoracic ones, occur associated with 

 segments I- VI and JX (figs. 3, 10) ; these are all placed 

 dorsally, and except the last are completely hidden from view 

 in the normal position of the abdomen. The first abdominal 

 spiracle occurs at the commencement of the abdominal stalk, 

 the second perforates the modified tergite of abdominal 

 segment II, while the 3rd-6tli spiracles lie between the 

 tergites and the longitudinal ridges. The absence of spiracles 

 to segments VII and VIII is doubtless associated with the 

 modification of the tergites in connection with the support of 

 the great colon and the median abdominal exudatory oi-gan. 

 The development of a spiracle associated with segment IX is 

 unusual ; perhaps it is formed in compensation for the loss 

 of spiracles in the two preceding segments. 



All the spiracles of the body are similar in structure. The 

 spiracular chamber is pear-shaped and bears a lai-ge circular 

 external opening, the internal aperture of the chamber is 

 minute, and there is a small occluding apparatus (PJ. XVII, 

 fig. 38a, 0. m.). There are no bristles of any kind guarding the 

 external aperture. 



It may be mentioned here that there is an esjjecially large 

 tracheal vessel in connection with the tritocerebrum (PI. XIX, 

 figs. 46 and 56). 



The Fat-Body and Blood-Tissue. — Although there is a con- 

 siderable amount of fat-body, yet it cannot be regarded as 

 very greatly hypertrophied or excessively abundant. In the 

 male the inflation of the abdomen is chiefly due to the large 

 size of the mesenteron and the hypertrophy of the male gene- 

 rative organs. In the thorax, short cords of large-sized fat- 

 cells are irregularly scattered and surrounded by coagulated 



