THE RABBIT TICK. 93 
ing August of that year was at least partially responsible. Engorged 
larve have dropped from rabbits as soon as the fourth day following 
attachment, but on a bovine 6 days was the shortest period of engorge- 
ment. The greatest number drop from the fifth to the eighth day, 10 
days being the longest time required for engorgement. 
TABLE XX V.—Engorgement of larve of Hemaphysalis leporis-palustris. 
| 
| Larve dropped engorged—days following application. 
4 Total 
siege = | Host. | number 
| 1 2 | 3 fag Hegde ey th Bede | dropped. 
Re eb Rt Pileliet. os alive hip cet aed ‘de I 
Sept. 30, 1907.....| Rabbit... 0/ of] of] o| 25] 27| 33 ae en 98 
eG 2, TOO... - 1-240. 25 <2 0 0 0 5 77 a 1 2 5 | 4 | 192 
Nov. 15, 1907. .... Bovine 0 0 0 0 19 75 | 27 11 | 2 | 0 134 
Mar. 11, 1908.....|... age eT by) OUT eT 13| 19 40" OV" 6 36 
Mar:.19,1908. . ..:\ese ee 0 0 0 0 | 11 131 115 24 0 | 0 281 
The molting of engorged larve was observed in 384 cases. Larvee 
which dropped in March at a mean temperature of 68.7° F. molted 
in 18 days, an effective temperature of 463° F’. having been required. 
The longest period passed before molting was for 2 larve which 
dropped November 22, 1907, and molted 134 days later. The mean 
temperature during this period was 61.98° F. Unfortunately our 
records do not include individuals which engorged during the summer 
months. 
The nymph (Tables XX VI, XXVII).—The greatest nymphal lon- 
' gevity observed was 342 days. This record was made on two nymphs 
which were collected on a rabbit on June 19, 1909, by Mr. W. V. King. 
One of a few nymphs which molted from larve April 19, 1908, lived 
for 307 days. A number of other lots of ticks, which were observed 
from the time they molted to nymphs, lived from 78 to 246 days. 
The longevity of a number of lots of collected individuals, which had 
become from slightly to one-half engorged, was from 34 to 334 days. 
The minimum engorgement period of nymphs which we have ob- 
served was 4 days, the last ticks dropping on the eighth day after 
application. 
TaBLE XXVI.—Engorgement of nymphs of Hemaphysalis leporis-palustris. 
a GIRS Sa SS EAE 8 te eee eS ae seme 
plied. ; : dropped 
1 2 3 4 5 6 7 8 9 10 
Oct. 29, 1907......| Rabbit... 0 0 0 0 0 2 1 0 0 0 3 
Feb. 25, 1908..... Bovine.... 0 0 0 0 0 1 0 1 0 0 2 
Apr. 4, 1908...... Ph aelee Se oe 0 0 0 0 0 3 6 | 2 0 0 11 
June 2, 1908......)... Uae 0 0 0 5 24 14 2 | 0 0 0 45 
May 22, 1909......| Rabbit 0 0 0 1 0 0 0) 0 0 0 1 
