72 CLAUDE FULLER. 



Fig. 100 (PI. VII) is a rare example of a duplicated post- 

 costal ill the presence o£ a duplicated cubital, and it will 

 lie noticed that the inner post-costal has crossed the radial 

 proximally to the base of the sub-costal. 



Fig. 101a (PI. VII) is a remarkable scheme that owes its 

 origin, in the first place no doubt, to the entrance of the 

 cubital into the wing-sac anterior to the medial. In intruding 

 itself into the middle region thus the cubital carried its 

 duplicated anal into a false position and the two anal tracheas 

 have grown enormously. As a consequence of this there is 

 only one normal trachea, the jjost-costal, present. An anal 

 intrudes between it and the radius ; the radius is reduced to 

 a simple trachea and the sub-costal has failed to develop. 

 The second anal intrudes between the radial and medial and 

 upon the medial falls the aerifying of the outer apical margin. 

 It accomplishes this by developing radial characters, pro- 

 ducing a series of three strong outer offsets. The cubital, it 

 will be noticed, crosses back again over the medial, fulfils its 

 normal functions, and at the same time produces two strong 

 branches to aerate the region normally supplied by the medial. 

 Fig. 101b illustrates the connection of the anal with the cubital. 



Fig. 102a illustrates the most extraordinary case met with. 

 In this wing-sac three principals are duplicated — the sub- 

 costal, the medial, and the cubital. The outstanding feature 

 of the scheme is the remarkable S course taken by the inner 

 of the two cubitals, but the grave disturbances are due to the 

 excessive development of the two sub-costals. This leads to 

 a somewhat similar condition to that seen in the wing-sac 

 illustrated by fig. 101a. Here, instead of the anals, it is the 

 sub-costals that bring about the atrophy of the radial, and 

 here, as before, the supplying of the loss falls on the medial, 

 the outer of the two medials assuming a radial form and 

 function. 



From the foregoing examples it will be seen that all the 

 principal trachea?, except the radial, are liable to duplication ; 

 all except the cubital, to a certain amount of reduction. In 

 only one case was anything approaching a duplication of the 



