INADEQUACY OF NATURAL SELECTION, ETC. 679 



quantity, differs in quality. Among bees, wasps, ants, &c., the 

 larvae of the reproductive forms are fed upon a more nitrogenous 

 food than are the larvae of the workers ; whereas the two sets of 

 larva? of the blow-tly, as fed by Professor Weismann, were alike 

 supplied with highly nitrogenous food. Hence there did not 

 exist the same cause for non-development of the reproductive 

 organs. Here, then, is one vitiation of the supposed parallel. 

 There is a second. 



While the development of an embryo follows in a rude way 

 the phyletic metamorphoses passed through by its ancestry, the 

 order of development of organs is often gradually modified by 

 the needs of particular species : the structures being developed 

 in such order as conduces to self-sustentation and the welfare of 

 offspring. Among other results there arise differences in the 

 relative dates of maturity of the reproductive system and of the 

 other systems. It is clear, a priori, that it must be fatal to a 

 species if offspring are habitually produced before the conditions 

 requisite for their survival are fulfilled. And hence, if the life 

 is a complex one, and the care taken of offspring is great, repro- 

 duction must be much longer delayed than where the life is simple 

 and the care of offspring absent or easy. The contrast between 

 men and oxen sufficiently illustrates this truth. Now the sub- 

 ordination of the order of development of parts to the needs of 

 the species, is conspicuously shown in the contrast between these 

 two kinds of insects which Professor Weismann compares as 

 though their requirements were similar. What happens with the 

 blow fly ? If it is able to suck up some nutriment, to fly toler- 

 ably, and to scent out dead flesh, various of its minor organs 

 may be more or less imperfect without appreciable detriment to 

 the species : the eggs can be laid in a fit place, and that is all 

 that is wanted. Hence it profits the species to have the repro- 

 ductive system developed comparatively early — in advance, even, 

 of various less • essential parts. Quite otherwise is it with social 

 insects, which take such remarkable care of their young ; or 

 rather to make the case parallel — quite otherwise is it with those 

 types from which the social insects have descended, bringing into 

 the social state their inherited instincts and constitutions. Con- 

 sider the doings of the mason-wasp, or mason-bee, or those of the 

 carpenter-bee. W^hat, in these cases, must the female do that she 

 may rear members of the next generation ? There is a fit place 

 for building or burrowing to be chosen ; there is the collecting 

 together of grains of sand and cementing them into a strong and 

 water-proof cell, or there is the burrowing into wood and there 

 building several cells ; there is the collecting of food to place 

 along with the eggs deposited in these cells, solitary or associated, 

 including that intelligent choice of small caterpillars which, dis- 

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