DEVELOPMENT OF SEX IN SOCIAL INSECTS. 



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selves. It seems to be quibbliii,L,' with the facts to insist that the 

 palpable failure to develop, which is exhibited, shall not be called " an 

 undeveloped condition," but that the structures shall be called 

 "rudimentary," and to build up assertions thereon, and when it is 

 stated that if "it be assumed that the number of ovarian tubes has 

 increased in the queen since the caste of workers arose, there can 

 nevertheless be no doubt that at the same time it has diminished 

 greatly in the case of the workers," the Professor appears to give his 

 own precarious position away, because he assumes a gradual develop- 

 ment in one direction, a gradual failure in the opposite direction, yet, 

 although he is willing to grant that the former is a more highly 

 developed condition of the ovary, he is not satisfied with calling the latter 

 an imperfect condition, but must insist, for the sake of the theoretical 

 superstructure, that the ovary is rudimentary, and his further state- 

 ment, that Adlerz discovered that the degree of diminution in the number 

 of egg-tubes differs in the workers of various species of ants, appears 

 only to enhance the position that it is a slowly produced imperfection of 

 the original ovarian structures Avhich has been produced, rather than a 

 development of something new. The " bursa copulatrix and the 

 receptaculum seminis have degenerated in the bee and ant Avorkers, 

 and we have every reason for believing that typical parts could never 

 disappear owing to poor nourishment, however poor it may have been." 

 We do not know on Avhat facts the Professor relies for this last state- 

 ment, but as a matter of opinion we are inclined to agree with him 

 that such parts would not disappear at once, but whether they would 

 "never" disappear is another matter. But what interests us here is 

 this, that in the bee and ant workers many, in fact most, of the 

 ovarian tubes have become atrophied, and it is only to be expected that 

 there should be a comparative failure in the structurally less important 

 parts of the ' ' bursa copulatrix' ' and the ' ' receptaculum seminis, ' ' because 

 the occasional laying of eggs by workers proves, as Ave have before 

 shown, that the essential egg-producing structures are still present. 

 These ovarian ducts, the Professor thinks, should no more disappear as 

 a result of the poorest feeding than " Avould a leg or wing." The 

 Professor asks, " How often have caterpillars been reared en masse on 

 starvation diet, either designedly or from carelessness, and yet none of 

 them has ever given rise to a butterfly destitute of wings, or to one 

 with only four legs instead of six. Such butterflies are always very 

 small, but in other respects perfect, just as in the case of the ill-fed flies." 

 Well and good, the Professor owns that they are smaller all round — 

 wings, legs, body, etc. The ill efl'ect of the feeding is not thrown 

 upon one organ more than upon another, but the whole structure is 

 less, and the four wings probably often contain only the same amount 

 of material as Avould be found in two if the larvae had been Avell fed. 

 Again, if this poor feeding were carried through several successive 

 generations, does the learned Professor think that no permanent results 

 would accrue ? But this is not all. It happens that butterflies do, as 

 the Professor points out, become imperfectly developed all round, they 

 preserve a sort of symmetrical condition, but moths often do nothing of 

 the kind. Ill feeding causes the latter to becomj crippled in all directions, 

 and moths with two or three atrophied wings, or with atrophied legs and 

 atrophied antennjii are the result; the disaj)pearance of an organ may 

 thus be an ontogenetic process, and although the Professor states that it 



