NEUTER INSECTS. 473 



of attention to each larva, rearing them all into perfect insects a 

 benefit also accruing to the earlier hatched larva? themselves, as they 

 sooner reach maturity, and can thus obtain an abundance of food with- 

 out rivalry. These earlier produced neuters have their reproductive 

 systems only slightly less developed than egg-bearing insects ; but nat- 

 ural selection, acting on the nurse, will cause them to grow less and 

 less. Reproductive organs that do not produce are of no use to their 

 possessors ; and, as this slightly less developed but useless reproductive 

 system would require more attention and more food from the fertile 

 nurse than would those larvse in which it was a mere rudiment, natural 

 selection, by working on the instinct of the nurses, would modify, alter, 

 or even suppress what was of no use. Or we may suppose that in the 

 distribution of food to the larvae the action is direct, some receiving 

 such a minimum quantity of food that the reproductive organs remain 

 rudimentary from want of material to build them up. 



The necessity of producing offspring quickly in early spring would 

 give rise to the instinct to feed the first produced brood of larvas on 

 food insufficient in quality, or in quantity, or in both. The eggs, then, 

 first laid by the female would develop into neuters. Neuters being 

 sterile females, they would inherit the instincts of true females when 

 they in turn took charge of the young. Whatever may be the worth 

 of this theory, it throws some light on the curious fact that with some 

 insects, as the bees and ants, the sexes are produced at different times. 

 With bees the queen first lays eggs which produce neuters ; then, at a 

 later period, eggs producing males. According to Gould, the female 

 of the Formica sanguined the red ant lays eggs which will produce 

 females, males, and workers at three different periods. That the habit 

 is so is well known ; but on the theory here supported can not we see 

 how the habit arose, and the reason why such a habit exists ? 



Thus far food alone has been supposed to affect the development 

 of insects, but there are several secondary factors ; size of cell being 

 one. Thus with the bee, the cell in which the queen is hatched is 

 larger, differently formed, and in weight said to be equivalent to one 

 hundred ordinary cells ; the cells from which emerge the males are 

 also larger than the cells of neuters. Now, the extra labor necessary 

 to produce these cells in founding a new colony, the extra labor in at- 

 tending to the inmates, and the non-necessity of having males or fe- 

 males at this early stage of colonial existence, are other reasons why 

 the first-laid eggs produce only neuters. At present and in this place 

 these points can be only touched on ; in the future they will receive 

 more elaboration. 



If neuters have arisen in the manner suggested, how has their in- 

 flexibility of character been maintained ? By natural selection modi- 

 fying the instincts of the nurse. What at first arose through the in- 

 capability of one or several insects taking care of many insects, be- 

 came through the action of natural selection, by the survival of those 



