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. 
Year Date Temp. No. Date Temp. No. Date Temp. No. 
1895 = == == = SS 
1896 Jan. 6 325 5,406 | Feb. 25 34° 7,852 Mar. 24 41° 57,267 
eRe) BoE 2,736 
1897 —S= — SSS SSS == —S 
1898 Jan. 25 3 2C 11,997 Feb. 22 B2¢ 6,318 
1899 Jan. 17 33° 20,800 | Feb. 14 33° 145,600 Mar. 7 oon 71,200 
Year | Date | Temp. No. Date Temp. No. Date Temp. No. 
| | | 
1895 Apr. 29 64° 86,867 = 
1896 Apr. 24 dae 233,436 | May 8 76° 54,365 | June i 69° | ~ 18,000 
ne. ala! io 35,200 
1897 Apr. 27 60° 472,000 === == ——= 
1898 Apr. 26 ayfe) 696,000 May 17 64° 195,200 | June 14 82° | 432,800 
| | | | ; = 
| | | 
Year | Date /|Temp. | No. Date | Temp. No. Date Temp. No. 
| | 
1894 | July 30 | 82°] 1,908 ‘| ——— es 
1895 |. July 6 81° Pal soy || ele, = al 79° 6,350 | Sept. 12 79° 19272 
oe eee 82° lly /S sya} 
1896 July 10 80° | 90,000] Aug. 8 86° 39.2008) —=——— — | —— 
S2at2S 82° 71,000 
1897 July 21 81° 172,000 | Aug. 24 78° 230,400 | Sept. 14 83° 50,000 
1898 Aug. 2 78° | 288,000 | Sept. 27 73° | 238,400 
23) 82° 96,000 | 
