REPORT OF II. G. HUBBARD. [9] 



As the motbs live aud continue to lay eggs for many days, it follows that the suc- 

 cessive generations rapidly become intcrniiugled aud confused. Any division into 

 exact periods is tlierefore by]>othetical, but the maximum number of generations can 

 be arrived at with certainty by combined observations in the tield and in vivaria. 



The follovfing statement exhibits in tabular form the conditions observed in the 

 field, together with the periods of time occupied in each stage of growth, as deter- 

 mined by numerous experiments made from time to time in vivaria indoors and under 

 iiettiuffs in the field : 



