igo8] Biological Notes on Potato Beetle 167 



August 23rd, on the next to the last mass of 51 eggs. As com- 

 pai-ed to the period during which the male was present, a period 

 of 34 days, 506 eggs were deposited in 21 masses ranging from 

 6 to 91 eggs and averaging about 24 eggs per mass, and with a 

 daily rate of deposition of about 14.9 eggs; there is apparently 

 some difference, as the daily rate of deposition fell after the male 

 left, though his absence did not seem to matter very much. 

 However, it is idle to speculate about a single observation of this 

 kind. The simple fact is that the female continued to deposit 

 fertile ova for many days after the male left. 



It is well to note in this connection, the fact that oviposition 

 in Pair No. 2 of the hibernated beetles stopped quite early, on 

 July 23rd, 24 days before the death of the male and 74 days before 

 that of the female ; the female of this pair therefore lived for fifty 

 days after the death of the male but deposited no eggs. I fail 

 to account for the lack of production during this period, and 

 merely mention the fact in order to show the singular difference 

 in behavior between the two pairs. In Pair No. i of the first 

 generation, both sexes disappeared beneath the soil at the same 

 time, whereas in Pair No. 2 of the same generation, the male 

 entered the soil fifteen days before the female, but again no deposi- 

 tion occurred after his desertion, and in this case but very little 

 before. 



5. Number and History of Generations Reared in the Labora- 

 tory. At 4 p. M., May 29th, 1907, as previously stated, two nor- 

 mal pairs of this insect were captured in copula in a potato field 

 a quarter of a mile west of New Richmond, Ohio, and these were 

 at once brought to the laboratory and confined, each pair sepa- 

 rately, in a suitable glass jar containing moist soil and covered 

 with cheese-cloth. They were kept constantly supplied with 

 fresh potato foliage and soon began to produce a continuous series 

 of eggs as shown in table II. These pairs were evidently hiber- 

 nated individuals and they constituted the parents of the first 

 generation. 



Eleven adults emerging from the soil at 12 130 p. m., July 17th, 

 being descendants of Pair No. 2 of the hibernated individuals 

 {cf. table X) were confined together with food on that date, and 

 on July 22nd, two of the pairs observed mating at 10 and 11 130 

 A. u., respectively, were transferred to separate jars; these 

 constituted the parents of the second generation. Pair No. i of 

 these two {cf. tables I and II) deposited 21 eggs which hatched at 



