146 LIFE HISTORY OF NORTH AMERICAN TICKS. 
The larva (Tables LIX—LXI).—As is shown in Table LIX, the 
greatest longevity of larve 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.—EEngorgement of larvx of Amblyomma americanum. 
Larvee dropped engorged—days following 
application. Total 
Date larvee applied. Host. number 
dropped. 
PE ZOSTER SAG IE eT AES 0 
Uke LOO neil Wena etree acetal. Boviness.-), 10.) On Sanlid |e calesOnt On Oa mrOn nO 264 
FRIDT1Gs tL OUS, (4 ps Else ee es Meee ses alee Gos ees 0 0 0 0 6 6] 0 2 1 0 15 
AL yi 27, 1 908.) 0) PWN eats eames ae | ae Gore aL 0h) Ol} JO; SOR) TSat Ol) Oe sO OuiO 93 
PATIET SU LOUS, Oips dialed onnre2 tenece et Rabbit...-| 0 0 0 | 61 | 21 | 10 4 0 0 0 96 
PANTO SG 1900). vb deancchin wc cceebansce Bovine:= =o) 07/05) 0) 201 ae eLOn Ont Ol eOnT KO 21 
The rapidity of engorgement is shown in Table LXT: 
TaBLe LXI.—Rapidity of engorgement of larvx of Amblyomma americanum applied to 
bovine at 3 p.m., July 12, 1907. 
Fevod Per cent 
Date engorged larvee dropped (bags examined), Number. : of total 
applica- | dropped 
tion. . 
1907 Hours 
Afb lhy sy wb Petes Heo Se ke sasees sacs cuneoresoosngoee sacar Een cnesesoaoee 26 68 9.8 
tivo wa Pee here ne toe see ls acnwcie eee cman Aestise Be IE es 51 72 19.3 
UW oils, C4 ob rao Ao SES Oa ote od aobcpon une Oda S ea aencceqesa ae 3 734 1.2 
Sil ga IG Ra NDE as a es Cee SSE er See SCUBA SM Ae On aeRO mae are ek 104 91 39.4 
Ml yal 6 sd GO psec as sc ss Sakae ee Sec owes amet ae oe creases ee eele see 69 943 26.1 
TLS IGS GN ee Se OF W SeeCASS OREO Teen Hem anor Abo Soe Ag onc Eco See ataGan an conar 4 974 1.5 
MGA, AO. Docc ncn case Seam bod 6 Bactvy SEoe a SE OeOn pesca Abas ene 5 1143 1.9 
ible ity: Sly eos paeee SRA eae Reeke Sop Mele Sayed Matera Mee Beer apeegs aa eee 2 1183 .8 
LUG UZ Si kt hehe Sc Beate anos Oe Be Da SOS ID pe oo Joe SNOOEE TE Ste GR ORAS c)= Oo)... eee psec noss:- 
ih 5 121 PA et iy eve Senedd aba OR Sd ONES Rte ape ectche e HG. MO? 8 ood Dea ee ee | i eee 
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 LXII-LXIV).—The most complete informa- 
tion at hand on the longevity of nymphs was obtained in an experi- 
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 
