April, '09] JOURNAL OP ECONOMIC ENTOMOLOGY 113 



Concerning the Number of Generations Annually 



In my opinion there are only three full generations in the vicinity 

 of Ealeigh. Some entomologists may be as surprised to hear this 

 statement as I was to discover the fact. Owing to the numbers of 

 nymphs present in the fields during November a fourth or fifth gen- 

 eration might be expected. However, there is a very strong argument 

 against that being the case. I was unable to secure eggs from any 

 terrapin bugs becoming adult later than September 1. A considerable 

 number were reared in the laboratory- and kept under observation to 

 determine this fact. Since we know that adult females may live and 

 deposit eggs for more than two full months, the presence of- young 

 nymphs in the field even as late as early December may be accounted 

 for, and they may be classed as belated indi\-iduals of the third gen- 

 eration. 



The statement that there are only three broods cannot, unfortu- 

 nately, be absolutely proven because I was unable to follow the devel- 

 opment during the summer vacation. However, the statement is de- 

 duced from the fact that the first generation at Raleigh, that is the 

 earliest maturing individuals, became adult on May 25, and deposited 

 eggs nine days later, or on June 4. These eggs hatched on June 8. 

 I found therefore that the first generation required fifty-one days, 

 not including eggs, from April 14 to June 4, to become full gro\^Ti 

 and deposit eggs, and subsequent rearing experiments do not show 

 much more rapid development during the hot months of summer. 

 Furthermore, May 25 is the date of maturity of the first individuals 

 of the first generation, while the majority were not mature until at 

 least ten days, or two weeks later. It may be true that some bugs of 

 the third generation mature before September 1 and commence to lay 

 eggs, but I feel convinced that the majority of the adults of this gen- 

 eration do not lay eggs, but live over winter as the hibernating form. 



Length of Life Cycle 



There is some variation in the duration of the young stages, partic- 

 ularly the 4th and 5th instars. Chittenden in Bulletin 103, Bureau 

 of Entomology', records the life cycle for bugs hatching in March as 

 70 days, including the egg stage, which covered 11 days. ]\Iy record 

 of bugs that hatched on August 24 and 25 shoAvs the life cycle, ex- 

 clusive of the egg stage, covered from 57 to 65 days. 



The following table shows the record of four individuals which 

 were kept in the laboratory — not heated — during the time recorded : 



