INVESTIGATION UT I-IKK IlISTOHV. 01 



It is ovi(l«'ut, howrvcr, tlint i^icjilcr reproduction takes ])l5ipc witli 

 old female beetles than witJi youn<j; ones, wlietlier tliey are attended 

 b}^ young males or old males. 



Some curious results of rearing experiments are given in Tables 

 XVII and X\'III, which were ])rc])arcd to sliow the length of lile of 

 atlults of this s])ecies. xipparently it is the habit of these beetles to 

 oviposit sparingly the first summer and freely during the second sea- 

 son. If conditions are very favoral)le the first year, a considerable 

 number of eggs may be laitl, while if they are unfavorable oviposition 

 is post})oned to the second or third summer as the case may be. It 

 sometimevs ha])])ens tliat eggs are laid the first and tliird summers, 

 but not during tlie second; at any rate each female will lay about 

 the same number of eggs, but the time when they are de])Osited 

 vai'ies greatly. 



The data secured from field colonies bear out tJiese facts. Two- 

 thirds of the larval colonies have shown some rej)roduction the year 

 following tJie planting, but in most cases tlu; rate was very small, 

 indicating that only a small ])roportion of the females laid eggs. By 

 cDm})aring the number of molted larval skins found in an adult 

 colon}' in Wellesley, ]\Iass., in 190<S, and those secured in the larval 

 colonies tlie year following their })lanting, it appears that tJie adult 

 colony of old beetles reproduced thirteen times as ra])idly as did the 

 larval colonies during the year following their liberation. This may 

 be exi)lainetl in part by the greater tendency of tlie young beetles to 

 disperse owing to scarcity of food or other natural causes, but it is 

 evident that they rei)roduce much more slowl3\ The jar records 

 indicate (see Table XY) that the old beetles multij)ly seven times 

 as fast as young ones and an average in the field of 10 to 1 in favor 

 of the old beetles would probably be about right. 



Polygamy. 



It has often been ol)served that females mate with the males several 

 times during the summer and it is j)robable that this is necessary in 

 order to insure the fertility of all the eggs. 



Xearly every year several jars have been ke])t under observation 

 where a single male was confined with 2 females and no cases have 

 been noted where infertile eggs were deposited. In the summer of 

 1908 a record was kept of two jars, each containing a male and 3 

 female beetles. The insects fed voraciousl}' and at the close of the 

 season 306 eggs had been laid in one jar and 618 eggs in the other (^ne, 

 all of whicli hatched. 



The average for each female in the first jar was 102 eggs and in the 

 second 206 eggs, botji of which are above the normal. 



Although it is not known ])ositively that each female in these jars 

 laid eggs, it is probable that this was the case, owing to the large 



