CONSTITUTION AND DEVELOPMENT OP TERMITES. 35 



furnish a means of escape from the considerable danger to 

 which the perfect insects are necessarily exposed. 



In other words, according to Miiller, Termites furnish royal 

 substitutes only if orphaned at a time when there are no 

 winged forms. Their procedure is really different, but the 

 comparison between them and plants possessing both perfect 

 and cleistogamic flowers still holds good. Calotermes may 

 be compared with a hypothetical plant, in which seed is pro- 

 duced by perfect flowers, and not by cleistogamic flowers unless 

 the others fall; Termes (in Sicily) to a plant in which the 

 perfect flowers do not produce seed, but the cleistogamic flowers 

 seed abundantly. 



The separate swarming of the sexes, discovered by myself, 

 fully confirms this conclusion. 



Lastly, the phenomena exhibited by Termes indicate an 

 advance on those found in Calotermes. 



8. It will be seen from the second appendix to the present 

 work that there is no direct evidence of relationship between 

 Termitidffi and Embiidse if we disregard the wings, which, 

 according to Westwood,^ Hagen,^ and Eedteubacher,^ are 

 somewhat alike. But Redtenbacher himself, the most com- 

 petent authority of the three, concludes that the Embiidse are 

 separated by the wing-structure as an entirely special group, 

 which exhibits relationship with the Termitidse and Blattidse, 

 as well as with the Perlidse.^ Thus there cannot be said to be 

 any close connection between the Termitid^e and Embiidse 

 even in wing-structure, while the number of the Malpighian 

 tubules, the arrangement of the testes and ovaries, the sper- 

 matozoa and alimentary canal, all present differences of the 

 highest importance. 



The Embiidse, it is true, lead a sort of gregarious life, but 

 they do so under conditions very different from those found in 

 Termes, since they show no sign of division into castes. 



1 ['Trans. Linn. Soc.,' xvii (1837), pp. 369—373, pi. ii.] 



2 ['Canad. Ent.,'1885.] 



' [Ann- K. K. Nat. Mus. Wien,' i, pp. 153—232, pis. ii— xx.] 

 * [A similar conclusion is arrived at by Brongniart, ' Insectes Fossiles,' 

 p. 2150 



