176 
TABLE 
LIFE HISTORY OF NORTH AMERICAN TICKS. 
LXXX.— Molting of engorged nymphs of Dermacentor venustus—Continued. 
Temperature 
Engorged nymphs molted—days following drop- | Number | from dropping 
ping. molted. | to date first 
tick molted. 
peer 
gorged 
nymphs Host. = 
dropped : J 2 Sa 
& | 32) 33| 34 | 35] 37| 40) 41| 42 | 43/46] 49/61] 71170) | 3 —|3/as 
S ol Sis & & gE 
= a gis ia Soe 
OO Sea 
AZ ala|e| a | (<4 
1908. hers OP kgs Ane 
May 18] Bovine....-.-.. 4b gees Aes ees eget | A | satel fore) ies allies 1} 1) 2) 88.5/68. | 78.6 
May 19): --.: doses stone 6} - lebeliocellosel|Socllsaae MONEE Slee 2} 2) 4) 88.5)68 | 79 
May 20|..... tne eee holt He ees eee se leete| see Gealecis Pee O| 3] 3] 88.5/68 | 79.1 
May 21]..... ie Al. walt Ole ioe ie ES 1} 2| 3] 89 |68 | 79.2 
AU |Gillesece GOS e ses SFA I ST =| PA Tee Save s}0d 3); LG OSM aia edank 
JNU hail fa Vee Shear (oo eae eee 13) <2|| Sse sss tealee = -| 10} 2} 12) 99 |73 | 86.5 
1909. | 
ANIS= 180] Guineas pigs |p lsc oe oleae sel ---| 1} O| 1/103 |77 (88.52 
Bent. was) anita. ss hocklt  Olesa tee PAN ase Se ee hee ieee cierale .-| 3] 2] 5] 95.5156 177.45 
Oct... 3.| Bovines:.: =... SSI cit She les ek ate ea 1d} 3) Of 3) 92.5)52.5)73. 25 
| 
1910. | 
Mar. 10| Rabbit........ 1 Ree ee cy DP ae ees ..-l1g}.--} 1] O} 1] 92 [43 170.55 
perk at rahe oe a pid Bete ae | eh aia | 19 setpcain sg U6 9] es ese 1} 1] 2) 89 [43 |70.80 
Apr. roundsquir- 1d 2d 
P ee Vig)... eae 192g o{pgps ht 3| | 11} 91 {43 70.86 
May 5] Foxsquirrel..| 5/1Q/1¢ {$}\.. aoe 2} 2! 4l100 |59 |76.27 
capt doe 4 (pao mapa eaten nS }-|-Aah Ris: Beheeie bale Paaais 10| 12} 221100 60 |s1.69 
May 30 Bost wee otek BN Se Bs toe Ge | ay an aD Ae ae 1} 2} 3/100 |66 |86.98 
June 131) Ground squir- 
Weloeee ese WGPs ase | Reese Saleen ates se es cee 2 roe pend ee ett erie era eer 6| 7} 13) 98 |69. 5/90. 63 
duly 20. | Guines pigh-..|) 12. -|-2<)-2-)2| ool oo |peel eee nie eee eee o) setae 1} O} 1/104 |77.5)89.50 
July 261 re ae squir- 
ee eee Wee il coc savoir Seale See cleeal eee 3] 7} 10/104 |79 |90.80 
July 291 Waddonncien: OE ss S| 2 Mt CR me A ee fl Et aa | an 1] 10] 11]104 |79 |90.07 
Use TO Rappibse-- sec a) ae VS te ieee yf, Nf eee Fe | fst 44 1) 5/103 |79 {91.27 
AUP LE iKGuines pig acss|l Slso4|os5|e acl esate leen| eee eee ees eee eee eee eee eee 1) 2| 3/104. 5/81. 5/92. 54 
AUPE Vs) Sea ibs se acer A exteledel ees eSalecelsules 15 of ae tel | eee pes be 2) 5} 7|104.5)73 |88.96 
Dols} Guinea pig ss sala se eclse eo) Sse toe all eee | Sees eet a eee eal eee 2) 5) 7|104.5)73 |88.94 
Auge WN. J. 6 (oy Ate eae 14 Fa VU Fem) UY Paar) el be || ee eb 5| 7} 12|104.5/73 |88. 85 
AIP SO lees Contec cee 5) (pe (RE eee | Se ae ee) FS 8 (Reel Ke S| | cee a 4| 2) 6) 98 |72.5/85.62 
Sept. 28 | Squirrel....... 1 ea a es RE SN lek | ae ee fe O} 1) 1} 91 |54.5/77. 68 
a a ee a es SE ee eee en eee 
Total..... i fare age ee fet Lu! | ie (ew ea |, =| Sl | a seal ee 79| S9|168|..- -c)e 2 ieee 
1 These nymphs were collected on native hosts in Montana when from one-half to fully engorged. 
The adult (Table LX XXT).—Of 355 adults, the sex of which was 
determined when they molted from nymphs, 172, or 48.5 per cent, 
were males. 
Immediately after molting both seXes are rather plump; 
the voiding of numerous pellets of white excrement begins almost 
immediately, and within a few days the thickness of the ticks is 
much reduced. The voiding of excrement continues for some time, 
but the amount is greatly decreased after the first few days following 
molting. 
Partial feeding in the nymphal stage has a marked effect on the 
resultant adults. The size is frequently reduced by more than one- 
half, the color pattern is often very weak or does not appear at all, 
and certain structures are affected. 
The longevity of the adults of this species is remarkably great. 
One male in a lot which molted to adults in June, 1908, lived between 
188 and 197 days. Three lots of ticks which molted between August 
