30 CLAUD K FULLER. 



to at fn'st voi>ard the second anxiliavy ns the principal lirancli 

 of the radius, but the following features convinced me that 

 it is a priiicipal : (n) the i"egularity with which the preceding- 

 trachea develops before any normal branches of the radial 

 trachen arise ; (b) the coinciding of its bi'anching' (when it 

 does branch) with the branching of the radial and other 

 principal trachete ; (c) the fact that it has occasionally been 

 found in a duplicated condition (in Calotermes) ; (d) the 

 occuri'ence of a gradual modification from a branched rib to 

 (•om]ilete atrophy. 



Holmgren attached sufficient importance to this rib to 

 name it the radius ; this supports my view that it is a principal, 

 l^adius is, however, an unfortunate misnomer for the rib in 

 question, and the application of the terui I'adial-sector to the 

 true radius is inapt. 



IV. THE TERMITE WING. 



In being deciduous the termite wing; possesses a striking- 

 character absent from the wings of all other insects. In text- 

 books it is usually stated of both ants and termites that thej^ 

 "shed" their wings, but the two cases are not analogous. A 

 part of the termite wing is shed, whilst a part is permanently 

 retained. For the permanent part there is no better term 

 than " wing-stump/' and to the temporary region (the blade 

 with which the air is .sculled in flight) "lamina" is applicable. 



These lamina? I regard as documents whereon is embossed 

 in hieroglyphs much of the early history of the termite wing- 

 ribs. It seems to me that the provision for shedding the 

 expanded part is, if not original, indeed very ancient ; and 

 that the habit of casting a part was acquired when the 

 venation was in a primitive, unspecialised condition. Hence 

 the laminae preserve evidence of a condition that must once 

 have prevailed. As a Rosetta stone was needed for the 

 correct interpretation of the writings of Egypt, so only by 

 looking into the development of the wing can the evidence 



