84 THE entomologist's kecoku, 



scanty supplies of food during larval life, the organs of reproduction, 

 or at any rate their essential parts — the ovaries — were normally con- 

 stituted, so that with good nutrition during the imago stage these 

 Hies reproduced in a perfectly normal manner," appear to us a mere 

 assumption, for Avhat proof has the learned Professor that there had 

 not been in certain directions imperfect development of the ovaries, 

 which only required a series of experiments in the same direction on 

 each successive generation, to show how far such imperfections had 

 proceeded. The case of social insects is not at all parallel, for the 

 habit has undoubtedly been inbred into these insects for countless 

 generations, and hence the cases in no wise resemble each other ; and 

 when the Professor goes on to assert that " by comparing the result of 

 this experiment with the known facts as to bees, the difference in the 

 behaviour of the two organisms is made clear. In the case of bees, a 

 distinct degeneration of the ovaries and various accessory organs of 

 reproduction takes place, in consequence of poor nourishment ; Avhile 

 in Hies the whole reproductive apparatus is formed quite as perfectly 

 when the nourishment of the larva is deficient as when it is ample," 

 we would like, to ask on what grounds the Professor makes this last 

 assertion ? If it be on the experiment he describes with Musca 

 vomitoria, then we must say that for a scientific man he is very easily 

 satisfied. Unless we are ready to grant the Professor this assumption, 

 his next statement that " meagreness of nutrition is a mode of reaction 

 characteristic of bees," that "it is a new acquisition, and was not 

 possessed by the ancestors of these insects," falls to the ground, and 

 as we believe that "meagreness of nutrition" does produce general 

 imperfect development in all insects, and base this assertion on 

 observations made in breeding, among others, many thousands of 

 butterflies and moths, we can only allow the Professor the assertion 

 for what it is worth. Ill-fed moths, for example, are small, and they 

 lay a less number of almost or quite normally sized eggs, as a rule, 

 and not the same number of smaller eggs ; a fact which strongly 

 suggests rather a reduction in the number of oviducts than a corres- 

 ponding reduction in the size of those still left (Vide, Ent. Record, 

 v., 138). 



Emery recently gave it as his opinion that the degeneration of the 

 ovaries of the workers was simply due to an increased sensitiveness of 

 the germ-plasm to poor nutriment, and explains the formation of 

 neuters as consequent upon an altered mode of reaction in this 

 direction in the germ-plasm. To meet the theory that "natural 

 selection " has undoubtedly inbred a tendency in the ovaries of these in- 

 sects to be more easily aiiected by defective nutrition than are the 

 ovaries of other insects, Professor Weismann asserts that the ovary 

 of the workers is " not only in an undeveloped condition, but is actually 

 rudimentary : the majority of the typical parts are wanting." What 

 does this assertion mean ? We know that Avorkers do sometimes lay 

 eggs ; therefore, at least, the essential parts are not wanting, and if we 

 accept the Professor's statement that the ovarian tubes are reduced in 

 nmuber from about 200 down to six, surely it is not to be expected 

 that the secondary structures connected with the ovarian ducts will 

 retain their most highly developed characters, for I take it that the 

 ovum is the primary essential structure, the ducts, receptaculum 

 seminis, &c., being secondary to the formation of the oval cells them- 



