CONSTITUTION AND DEVELOPMENT OF TERMITES. 65 



Lepismidse, and the respiratory apparatus is therefore holo- 

 pneustic. The anterior pair is situated latero-ventrally : seen 

 from above, they lie on the line of junction between the pro- 

 notum and raesonotum ; seen from below, they lie in front 

 towards the hind margin of the prosternum. The second pair 

 is also latero-ventral ; seen from above they appear to lie be- 

 hind the anterior margin of the metanotum, and from below 

 behind the anterior margin of the metasternum. Further, the 

 position of these two pairs varies with the degree of contrac- 

 tion of the body. The remaining pairs are also lateral, but lie 

 nearer the dorsal than the ventral surface ; the line con- 

 necting any given pair would cut the tergite at the junction 

 of its anterior fourth with the remainder. 



The tracheae are very numerous, without any dilation. 

 They anastomose by longitudinal and transverse branches, 

 which are repeated in most of the abdominal segments. The 

 transverse branches are ventral and unpaired ; they unite the 

 tracheal system of one side with that of the other, or rather 

 form a transverse canal between each pair of bronchi (as I call, 

 with many writers, the trunks which originate from the stig- 

 mata), e. g. between the sixth right and the sixth left bronchus. 

 Similar anastomoses are met with in the Lepismidse, Ter- 

 mitidoe, &c. The remaining anastomotic branches are paired 

 and longitudinal, and of two kinds, ventral and dorsal. The 

 former serve as a communication between the transverse 

 anastomotic branches, their anterior terminations lying more 

 laterally (externally) than their posterior. The dorsal branches 

 connect the dorsal transverse tracheal branches, and form 

 longitudinal dorsal trunks, such as exist in the Lepismidse. 

 These anastomoses will be more clearly understood by observing 

 that each stigma (e. g. the sixth right) gives rise to a single 

 bronchus, which turns forward, and after a short course gives 

 off a branch to form the transverse ventral anastomosis with 

 the corresponding branch of the opposite side (continuing the 

 illustration, from the sixth left bronchus). A little in advance 

 the same bronchus gives off a trunk which runs transversely to 

 the dorsum, and furnishes branches of the second kind, forming 



VOL. 40, PART 1. NEW SER. E 



