146 LIFE HISTORY OF NORTH AMERICAN TICKS. 
The larva (Tables LIX-LXI)—As is shown in Table LIX, the 
greatest longevity of larvee observed by us was 279 days. This 
record was made on ticks kept in a tube in a protected place out 
of doors. The longevity of larve kept in the laboratory did not 
exceed 176 days and usually ranged between two and four months. 
Larval engorgement was completed as soon as 3 days, the greatest 
number dropping from the host on the fourth day. The longest 
period required for engorgement was 9 days; this, however, may be 
explained through the failure of the ticks to attach at once or because 
they attached at a point where the blood supply was poor. 
TaBLe LX.—Engorgement of larvxe of Amblyomma americanum. 
Larvee dropped engorged—days following 
application. Total 
Date larvee applied. Host. number 
dropped. 
Pape2 eS Teas Ge Eee S es9 
Julbyet2 A907 .3 (psd: sas onaseeer eee es Bovine? 25); Oe On Sa Lie lieedal. OF| One Onan 0 264 
Aor 26 1908, Anp. makes Sees ssa SranGOL Sacco) OMe OM 1OMIERON RG ahe Gul) Orth 2ulwe deka 15 
Duby 27; AOS corp Wesco cei see oe Soe COW see OF Oo O80 Tel Os SOR ON On O 93 
AUS SILOS toNp- wiles Loerie ods 28 Rabbit. 222) 70) 0 F710) 60 |, 215) 103) e465) KOF |) Oy 20 96 
SURG OOO est ees cick Oe eo eae ae! Bowness.) 10.0.) O05) 200 115) 105), On iOS On a0 21 
The rapidity of engorgement is shown in Table LXI: 
TaBLe LXI.—Rapidity of engorgement of larve of Amblyomma americanum applied to 
bovine at 3 p.m., July 12, 1907. 
Period 
frail Per cent 
Date engorged larvee dropped (bags examined). Number. aaniie of total 
pplica- | gropped 
tion. pped: 
\ 2 
HO Hours. 
Sui seat bs a Is oye ee, Ce Ree a ee RG eee See erie See aa ee 26 68 9.8 
JULY: LDVS PMs ss acise see tee lable Seisorac Weeks Se BE ices Ee ete ee openers 51 72 19.3 
Sulive 5, 4.30 MM. 8520 eae hast es ck ae aes -eoeee os sae ee see = 3 734 1.2 
sitTy GS UO ea ea estate evi Nee ca ees ey are geste el caper gre reg tre SR 104 91 39.4 
Fee LG; st 30 yp oe, ae eR ee ee oe revere yeh ene i eee ne eat 69 944 26.1 
RUT UG be BINS ae Sor ate ae SO te een ee ree AE eee eet eee ieee eee te 4 974 1.5 
Sly Li LO aims. oh yak care chek o = 2 ieieidy sy Sialala, Sete Soe eee Sy oie eae 5 1143 1.9 
JULY? L752 Ds WS So fo Sd akoe is a eitel gisele ae Sane ew 2 I er cereals ie ae yey yee oe 2 1183 8 
July 17; PMs fe Bes ewe se soos eke Sete enioe heen oe aie eran eae ae 0 eee eee 
ee ee a eel mE RB MiP en cianicht lp deca ah Wl A 204 | 
Our observations of the molting of engorged larve were made on 
326 individuals. In July and August at a mean temperature of 
86.78° F. molting commenced in 8 days. A total effective tempera- 
ture of 350° F. appears to be required for this transformation. The 
longest period recorded from dropping to molting was 26 days. 
During winter this period would undoubtedly be much longer. 
The nymphs (Tables LXTI-LXIV).—The most complete informa- 
tion at hand on the longevity of nymphs was obtained in an experl- 
ment in which 30 nymphs that molted June 23-26, 1907, were kept 
out of doors in a tube that had a cork stopper, through which a 
small hole had been made and a small glass tube inserted to permit 
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