1908] Biological Notes on Potato Beetle 175 



These being true, the facts recorded by me in regard to the pro- 

 duction of a third generation are indeterminate in value, and 

 exceptional in nature, for apparently there were neither abnormal 

 environmental factors present, nor variation tending to racial 

 evolution. It would be highly interesting and important, there- 

 fore, if more of this breeding of annual cycles under normal or 

 natural conditions, was carried on, in two similar series, in the 

 laboratory and in the field under as natural conditions as possible. 

 The question of the number of annual generations of decemlineata 

 freely breeding in nature has not been determined yet by actual 

 experiment, or at least such are not recorded with cold evidence, 

 and Tower (1906) has not decided it, but perhaps left it in a more 

 controversial position than ever; he has, however, made a long 

 stride in the direction of settlement. 



But looking at it from another standpoint, I believe that 

 Tower (1906), although in the proper place (lb., Chapter IV, 

 p. 243) not presenting definite data upon which his conclusions 

 are based, has the best right to be followed because of his large 

 experience with breeding the species in question. As I under- 

 stand it, he speaks of normal, average conditions in nature, and 

 I do not know that any direct or definite evidence has yet been 

 presented to show that the species is more or less than double- 

 brooded in nature, and Tower certainly has had enough experience 

 with decemlineata in nature to speak with authority on the sub- 

 ject. There are certainly as many as two annual cycles, if re- 

 peated laboratory experiments can be at all trusted, and Knab's 

 (1908) recent contention that there is but one, based on the 

 systematic relations of the beetle is not tenable, and to my belief, 

 wholly without basis or foundation for advancement. The ques- 

 tion now is : Are there but two, or more than two annual cycles 

 with decemlineata; or, in other words, does the second generation 

 reproduce? This does not concern any other species of Leptino- 

 tarsa or species of Calligrapha, Lina or Gastroidea, but the sole 

 species under consideration. 



I have myself recorded reproduction by a first reared genera- 

 tion of Gastroidea cyanea Melsheimer (Girault, 1908, p. 8), 

 making two annual cycles possible, but I can't see what the num- 

 ber of generations in closely related genera of the family has to do 

 with the question at issue, especially since the question with these 

 genera is not established. It was also going beyond the point to 

 say that the seeming double-broodedness of decemlineata "may 



