476 THE POPULAR SCIENCE MONTHLY. 



munity, these parts would decrease in size ; if the females no longer 

 assist in building, if their entire duty is to lay eggs, their wings, legs, 

 jaws, etc., will decrease ; the surplus of force thus entailed being add- 

 ed to the reproductive system. Thus, then, there would have been 

 produced the four castes found among the termites ; the soldier rep- 

 resenting the typical male of the species, the workers the typical fe- 

 males minus the perfected reproductive organs. But and here is the 

 great difficulty how can the changed male have given his lost organs 

 to his sex, and the female have transmitted her original but now 

 modified peculiarities to the workers ; especially as neuters do not 

 propagate, and hence can not transmit their characters to progeny? 

 Another law solves a portion of the difficulty : peculiarities acquired 

 at any period of life are apt to appear in the same sex at the same 

 time of life. Disuse having wrought its changes on our fertile insects 

 after they had reached their perfect form, we can not expect them to 

 appear in offspring which never reach this form. The modifications 

 of structure were produced that the reproductive system might be 

 benefited ; why, then, should they take place in those insects which 

 have a rudimentary and hence useless reproductive system ? 



We have now to ask whether those larva? which are to produce fer- 

 tile insects resemble, in any stage of their existence, the larvae which 

 are to produce neuters ; whether, for example, the fertile male termite 

 resembles, at any time, the infertile soldier. The reply to this is 

 partly positive, partly negative ; the larva of the female termite re- 

 sembles very nearly the larva of the worker ; but there is no great 

 resemblance between the male and the soldier larva?; there is a greater 

 resemblance between the pupa?. 



The fact alone that the female of social bees, and the male and fe- 

 male of white ants, should be presented under two forms is no novelty 

 in insect history. In the aphides or plant-lice a similar state of affairs 

 obtains : there is the perfect and imperfect female. Even as high in 

 the scale as butterflies dimorphism is not uncommon. Mr. Wallace 

 has discovered two forms of the female of Papilio 3emnon, an inhab- 

 itant of the East Indies, one of which has tailed wings, the other of 

 which is tailless. Several butterflies have three kinds of females, or 

 are trimorphic. Hence the mere differences between neuter and per- 

 fect insects are nothing unusual, considered as differences. Were the 

 workers fertile and thus able to propagate their peculiarities, the diffi- 

 culties would vanish ; but the problem why a fertile female should 

 give birth to two or three distinct forms is still shrouded by mysteries, 

 accept what explanation we may. 



Our alternative that the workers are the type from which the 

 males and the females have diverged is only an hypothesis, but in 

 view of the facts it is the only alternative left us ; since the neuters 

 themselves can not have diverged from any type on account of their 

 sterility. 



