lyo Annals Entomological Society of America [Vol.1, 



sumed." And again on page 244: "In all the species of the 

 genus the only difference between the two generations is that 

 the second does not develop the germ-cells until after a period of 

 rest, while the other develops them at once, or soon after emer- 

 gence." 



Although these statements are not very clear to my mind, 

 because of certain ambiguities*, yet the following schema repre- 

 sents my interpretation of Tower. This schema, for the con- 

 venience of comparison with the one in foregoing (p. 168), is 

 based on two pairs for each generation. 



Schema representixg an Interpretation of Tower's Generations of Decemlineata. 

 Pair No. 1 Hibernated pairs Pair No. 2 



Parents of Generation No. I 



Generation No. 1. 



Pair No. 1 V Pair No. 2 



Parents of Generation No. H 

 Generation II 



-) Pair No. 1 V Pair No. 2 f 



Hibernate r Adults of Generation II j Hibernate 



By comparing the two schemata, it is at once apparent that a 

 portion of a third generation is represented by my observations, 

 and this is clearly in disagreement w^ith the reiterated statements 

 of Tower, to the effect that the adults of the second generation 

 do not breed, or even show signs of breeding, before a period of 

 hibernation or aestivation. This fact would not be considered 

 of much importance, owing to the laboratory conditions and 

 meagreness of the observations, were it not for the statement made 

 by Tower {lb., p. 246) that "In decemlineata I have not by any 

 process been able to prevent this preparation for hibernation in 

 beetles which should normally hibernate. ' ' The mating and repro- 

 duction of the adults of the second generation are therefore very, 



* For example, the two successive sentences on page 243: "The sccojid genera- 

 tion docs not develop the germ-cells nor show any reproductive activtiy until 

 after it has passed through a period of hibernation or aestivation." and 

 " Beetles are found breeding even late in the autuinn, but these are the bela- 

 ted individuals of either the first or second generation." It is clearly im- 

 plied in the last sentence that beetles of the second generation breed, which 

 flatly contradicts the declaration of the first; there exists a confusion of 

 terms both here and elsewhere in the discussion. The italics here are mine. 



