1S04.] 571 



refutation of Old Error is at least as important an occupation for the 

 naturali^^t as the exposition of New Truth. Otherwise, if we all busy 

 ourselves in the publication of what each of us considers as new truths, 

 and nobody takes the pains to winnow away the falsehoods from the 

 enormous nuiss of observations accumulated by his predecessors. Sci- 

 ence soon becomes a mere heap of chaiF with only a few kernels of 

 wheat mixed in amongst it. I know no entomologist, living or dead, 

 who has not made some grievous mistakes ; and I candidly confess that 

 I have myself made several most inexcusable ones. The difference 

 between the pretentious charlatan and the truly scientific entomologist 

 is. that the former claims to be infallible and invariably gets angry 

 when his errors are refuted and corrected ; the latter always acknow- 

 ledges and corrects his own errors when he is fortunate enough to dis- 

 cover them himself, and is thankful to any one else who will take the 

 trouble to correct them for him. The former writes and talks for vic- 

 tory and not for truth ; the hitter for truth and not for victory. " By 

 their fruits ye shall know them." 



Thus far we have been dealing with natural phenomena. We now 

 approach a subject which may be considered as verging almost upon 

 the supernatural and the miraculous. If we can believe what is as- 

 serted by a Russian naturalist, the larvae of Gecidomt/ia differ, not only 

 from the larvae of all other known insects, but from all known animals, 

 no matter to what Class they belong, in propagating their species while 

 they are still in the larva or immature state. I am indebted to Baron 

 Osten Sacken for furnishing me with the following account of this most 

 astounding revelation ; — 



About a year ago Wagner, a Russian naturalist and a good anatomist, published 

 a large folio work in the Russian language, illustrated by numerous plates, re- 

 lative to certain observations which he had made on Gecidomyia. He asserts that 

 some larvse of this genus, which he found under the bark of trees in winter, 

 breed young ones ! In other words, that during winter a second generation of 

 larvse is developed within the bodies of the lirst, that having reached a cer- 

 tain stage of growth these larvfe leave the bodies of the mother larvae (se- 

 veral from each), and that they grow and afterwards produce a third gene- 

 ration in the same manner. This goes on till spring, when the last generation 

 is transformed into flies. Thus the reproduction of these Cecidomyia would 

 have some analogy with that of Aphis. A mother larva usually, he says, gene- 

 rates from 7 to 10 young larvae, and at a certain stage of their growth she be- 

 comes half-dead and hardly moves, and finally dies, when the young larvae 



