204 



recurrent pulses at approximately monthly intervals. In Plate V. 

 I have plotted the seasonal distribution of this species for the years 

 1894-99. The plate will serve as one of the best illustrations of 

 the nature of the data contained in my statistical records that could 

 be chosen from them. It illustrates graphically the character of 

 the seasonal distribution of this species and the nature of what I 

 have called recurrent pulses. 



In the table which follows, as elsewhere in similar tables, these 

 pulses are listed by the number of individuals attained at their 

 maxima, and are located according to the dates of these maxima. 



PULSES OF POLYARTHRA PLATYPTERA. 



