ca 
THE ROTUND TICK. 85 
recorded were shriveled and brownish and failed to hatch. Another 
fully engorged female, collected on a dog, March 29, 1910, began depos- 
iting on April 28, and deposited 130 eggs during the next 5 days. 
A few days later this female began to turn dark and soon died. The 
eggs deposited failed to hatch, thus suggesting that the tick may not 
have been fertilized. 
The minimum incubation period observed was 26 days. This 
record was made in the laboratory during September, 1909, when the 
mean temperature was 85.67° F. A maximum incubation period of 
53 days occurred during August, September, and October with a 
mean daily temperature of 84.58° F. The total effective temperature 
required for embryonic development appears to be at least 1,109° F. 
TaBLE XX.—Preoviposition, incubation, and larval longevity of Ixodes kingi. 
| t. 
Temperature during incuba- 
1% tion. 
E dj|D i- | Hatch oe 
ngor, eposi- atch- 
ecole tion ing incu- All larve dead. Bopckts pees, 
collected. | began. | began. | bation EeVIKy- see | Total 
period. Max.} Min. dail ef- 
mea, | Wttive 
1909. 1909. 1909. Days. Days. 2F’. Fey fi, Be 
June 29..... July 25 | Sept. 1 39 | Feb. 25-Mar.30,1910.| 177-210..] 110 | 77 89.32 | 1,806.5 
esate uly 29 ae <1 RS ie ae eer en eye cs me om i 89.25 | 1,618.8 
10 70 eae Aug. 13°'| Oct. 4 53 | About May 1,1910..; About| 110} 66 84.58 | 2, 203.7 
178. 
ee ..- Aug. 10 | Sept. 28 Se her ek Peewee SE aan Soe 110 | 56 84.74 | 2,387 
Desi n-; Aug. 15 | Sept. 29 OG ss Sets. - ey. sek et oe 110 | 56 85.34 | 1,947.6 
Dav... Aug. 18 | Sept. 24 38 | Apr. 27-July 19,1910 | 215-298..| 110 | 61 86.65 | 1,658.7 
Dass: .. Sept. 1] Sept. 26 OG) | ease pete eee so Ret EE ee ee 101 | 61 85.67 | 1,109.4 
1910. 1910. 1910. 
Mar, 29..... Apr. 27 | June 17 52 | Before Sept. 25, 1910.| 100...... 100 | 62.75 | 75.36 | 1,682.7 
70) ay (ae ay 16] June 24 AO es asd 2b. S522. Ast eeetae . 100 | 60 80.61 | 1,504.4 
MAY Cen cs June 1) July 14 pF ST 2) ot Pan 3s a ee 1 es 100 | 66 84.51 | 1,826.4 
June 18..... July 5| Aug..5 O20) Webs 4h01le o. u03-t BSS! ecg? 104 | 73 88.09 | 1,442.9 
The larva (Tables XX—XX1T).—The larve of this tick have been 
found to live at least 215 days. The lot upon which this record was 
based hatched September 24, 1909. Fifty were still alive April 27, 
1910. Other lots hatched in midsummer were found to live nearly 
as long as the one cited. Larve may drop engorged as soon as the 
fourth day after application to a host, while some may remain on the 
host 16 days and even then not become fully engorged. Although no 
engorgements were obtained from two or three lots of larvee applied 
to bovines and guinea pigs, most of the lots tested attached readily 
and a large percentage of them engorged. Attachment was found to 
take place usually within an hour after the time of application to a 
host. Many specimens were found detached from the host when they 
were from one-fifth to two-thirds engorged. This premature drop- 
ping is probably due to the ease with which they are displaced by the 
host animal after they have become partially engorged. 
