igoS] Biological Notes on Potota Beetle 173 



period to hot, dry conditions, during which time they laid 409 

 eggs. For the latter half of the reproductive cycle they were kept 

 in normal conditions, laying 840 eggs. From the 409 eggs devel- 

 oped and laid in changed surroundings I obtained 64 adults, as 

 follows : 



"A( i) Normal (apparently) decemlineata, 12 males, 8 fe- 

 niales; (A 2) L. pallida, t 10 males, 13 females; (A 3) L. immacu- 

 lothorax,* 2 males, 3 females; and (A 4) L. albida,t 9 males, 7 

 females. These four lots were separated and reared, with the 

 exception of pallida. The 840 eggs laid in normal conditions 

 gave 123 normal decemlineata, and these I designated B. 



"The Lots A I and B were reared side by side in the following 

 generations and both gave normal beetles as far as could be deter- 

 mined, but as the period for hibernation approached, those of Ai, 

 instead of going deep into the ground, as did B and as is normal, 

 aestivated on top or close to the top. The Lot B went into hiber- 

 nation in September, A i in late October and early November. 

 In January (January 2) Lot A i emerged from aestivation and 

 began breeding, giving a brood, part of which hibernated and 

 part continued breeding for five generations, then hibernated, 

 and then emerged and bred through five more generations. These 

 hibernated again, and in the fourth generation of the third cycle 

 of five generations were killed in July, 1904. These successive 

 generations were all reared under exactly similar conditions, nor J 

 was there any conscious selection practiced. Free interbreeding 

 in each lot was allowed. The general result is expressed in text- 

 figure 26. 



"This race with a cycle of five generations is of great interest, 

 showing the profound modification resulting in the reproductive 

 cycle. None of the beetles of the lineata group, to which this 

 beetle belongs, have more than two, or rarely three generations 

 per year, and there are none known in the genus that have over 

 three. Clearly, then, this race with five generations in each cycle 

 is quite a new character in the genus, and was, as far as discovered, 

 constant 1 1 from the start, showing in the fourteen generations no 

 tendency to revert to the parental standard. As far as I can 

 discover, this case can be explained only as the direct response 

 of the germ plasm to the extreme stimuli used in the experiment. 



* L. decemlineata pallida Tower; L. decemlineata immaculothorax Tower. 

 t L. decemlineata albida Tower. (Cf. p. 92). 

 X Beginning p, 289. 

 II Beginning p. 290. 



