THE OPEN TYPE OF WING-GROWTH 83 



individuals with developed reproductive systems, but with 

 wings always in a rudimentary state, known as complementary 

 or substitution " royalties ", are kept in case of accident to 

 the true royal pair. Thus the termites afford examples of 

 various stages in the arrest of the normal development of 

 wings on to the total disappearance of those organs. 



In several groups of termites it has been noticed that after 

 the last moult but one, the nymph spends some time varying 

 from an hour to three days in a quiescent state, motionless 



a 



FIG. 44. 



a, Early larva of North Indian Termite (Archotermopsis) with 

 wing-rudiments (r). x 5. After Imms, Phil. Trans. R.S., 

 1920 ; b, resting larva of Termite (Rhinotermes), lateral view. 

 X 5. After Holmgren, Zool. Jahrb. Syst. XXIII. 



and without feeding (Fig. 44 b). In some cases it lies on its 

 side in a chamber or passage of the nest with the head bent 

 ventralwards and the feelers directed backwards alongside 

 the legs. This condition is noteworthy, for it suggests the 

 pupal stage in the life-history of such insects as butterflies and 

 beetles. And it may suitably lead on to the consideration of 

 some insects of other groups, in which such a resting-stage 

 forms a constant and prominent feature, although they conform 

 to the same visible type of wing-growth. 



Gardeners are familiar with small elongate insects, known 

 commonly as Thrips, which often live in numbers on the 

 leaves and blossoms of plants, whence they suck sap, often 

 causing thus considerable injury. They form a special order 

 (the Thysanoptera l ) characterized by the curious feelers with 



1 H. Uzel : " Monographic der Ordnung Thysanoptera ". Koniggratz, 

 1895. W. E. Hinds: "Thysanoptera inhabiting North America." Proc. 

 U.S. Nat. Mus. xxvi., 1902. 



