176 LIFE HISTORY OF NORTH AMERICAN TICKS. 
TaBLE LXXX.—Molting of engorged nymphs. of Dermacentor venustus—Continued. 
Temperature 
Engorged nymphs molted—days following drop- | Number | from dropping 
ping. molted. | to date first 
dick miaieek 
Daloan- @ J 
gorge 
nymphs Host. pe) 
dropped. ’ A 71a 
& | 32| 33| 34 |35|37| 40] 41] 42 | 43) 46] 49/61] 71|170) || 5 zs 23 
: d/e/2| 8 |B /5° 
| 5 A= | 
Al | Ala|ae| a /al< 
—|—| 4 i eel 
1908. | o FP Fl? ee 
May 18] Bovine.. 7 Seales aaca ese eae SEL ts dele al es 1} 1) 2) 88.5)/68. | 78.6 
May 19 do Sel ered aS 5 Neri [or eel Pet ft Ae Wed ete ele 2} 2) 4) 88.5/68 | 79 
May 20 Meee Ml wre bos ese Ge lie be sa rie) oe Ea 0} 3) 3] 88.5/68 | 79.1 
May 21 Ces Boel ese ese (ed seer OH [h starelfe 1} 2) 3) 89 |68 | 79.2 
Aug. 6 sy ese [Is a Dl be a Pee |e 11) 5) 16) 99 173 | 87.1 
Aug. 7 T3\e 355)[3-|\533 Slee ones 10} 2} 12) 99 j7 86.5 
1909. | | | 
Woe Sse Guinoapig: oleae s | Bale ealeeele wer alae bee ---| 1] 0} 1/103 |77 |88.52 
Pepto) Rabbits. s-s2o-|| Poles|ote)-eaelen lesa] saleme eee. aa 3) 2} 5) 95.5)56 |77. 45 
Oct.) 3) “Bovine!=; 5... Beale eels tahebel site ers |pereli Serer 1d} 3) O} 3} 92.5)52.5)73. 25 
1910. 
Mar. 10} Rabbit........ 1 Se eee rae) |S BA) se erie Bee | Wo oh hs 1} OF} 1) 92 [43 |70.55 
sian. - pede! Oe 7 Se aS he a Solera al Pisoalscaiece 1d'.-.|--.} 1] 1] 2] 89 |43 170.80 
pr. xround squir- 1g |\2d 
2 eel Miah... a SR ae tl 19 29 o{h¢ Beit. i 3| s| 11] 91 [43 {70.86 
May 5| Foxsquirrel..| 5/19 ig {1g} BES 2} 2! 4l100 |59 |76.27 
May 161) Ground squir- |\,-|5¢ ld 
2 ee it a analy 43 | Bee ea PEAR Ba cp 10] 12} 221100 60 |s1.69 
May 30] Bovine......-. aay ie emater| = eel tele ere ol otra ete oe trees 1} 2} 3/100 (66 /|86.98 
June 131) Ground squir- 
reli eek i CG A Be) be ea ha Ue (mie Fr Lee - | al| e | 6} 7} 13) 98 |69.5|90. 63 
July 215) Guineapige ccnp ll eac| abe |sces lene |eccle oe |e aera lee eee lees eee 1} O} 1/104 |77.5)89.50 
July 261 pone squir- 
Be ite seis Oj1d'}-- a el asics ASeilleee apaee|ecerceacs | eae -| 3) 7| 10/104 |79 |90.80 
July 291 Wondchuck. gS) Pape es ya Pee | Sa | yal a Tee |e Se eel | See -| 1} 10] 11)104 |79 |90.07 
ipo ts taboite. oo. 6]. - -| 4] 1) 5/103 79 91.27 
Aug. 11 | Guinea pig. ... -| 1) 2) 3/104. 5/81. 5/92. 54 
Aue. 187] Rabbits. 2... -| 2} 5| 7/104.5/73 |88.96 
Do...| Guinea pig -| 2| 5] 7/104.5/73 [88.94 
Aape eis... GOsr2ct -| 5) 7| 12)104.5}73 88.85 
7 Xi et (Be Goske-t2-2 -| 4] 2) 6) 98 |72.5)85.62 
Sept. 28 | Squirrel....... -| O| Jj 1) 91 |54.5/77.68 
Total-..<. 79) (SONG8|ce ec cleees peer 
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 
