THE CATTLE GRUBS OR OX WARBLES 65 
tendency to dig into the ground is not very marked. Not infre- 
quently specimens will bury themselves in loose débris, such as straw 
and broken leaves, but they do not burrow into compact soil or sand 
to any extent. The larve show marked negative heliotropism, and 
one was observed to crawl more than 10 feet, seeking shade in which 
to pupate. Usually within a few hours they become quiet and within 
1 to 12 days the integument hardens and. changes its shape into the 
typical puparium form. The average prepupal period recorded in 
the case of 238 larvee of H. lineatum was 3.4 days. Representative 
records are presented in Table 8. The prepupal stage observed 
among 7 specimens, kept in a screened insectary in Middletown, 
N. Y., in 1922, ranged from 1 to 4 days. This period may vary 
several days in the case of larve leaving the host the same day, but 
the total time required for their transformation to adult is not in- 
creased to that extent. 
It is evident that where the larve drop normally the prepupal 
period is markedly influenced by temperatures. 
The pupal period at Dallas, Tex., ranged from 16 to 75 days, the 
average being 38.2 days, as recorded for 196 specimens. Representa- 
tive data are given in Table 8. 
TaBLE 8.—Duration of prepupal and pupal stages of Hypoderma lineatum at 
Dallas, Tex. 
Larvs emerged F Temperature 
from host : Pupated Flies emerged Period| dropping to adult 
Pree from 
onal Pupal| drop- 
- q Ba oa NG Sasa period ping Aver- 
Num- er 0 0 P age 
Date nen Date ber Date bet of fe- adult | Max-| Min. daily 
males mean 
1916 1916 Days 1916 Days | Days | °F. | °F. | °F 
Hepety—- 225 2 1 | Feb. 21 1 344| Mar. 21 |______- 1| +2 33 | 91.5 | 23.7 | 58. 26 
Feb. 18___--- eae dose 1 3 Mar. 20 | Cea Rea ee 28 31 | 91.5 | 23.7 | 57.71 
Feb. 21__--__ 1 | Feb. 22 1 34| Mar. 21 Dah ees eah ae Et +28 29 | 91.5 | 23.7 | 58.94 
Que 1 | Feb. 23 1 2eel ear 22) gasses 28 30 | 97.9 | 23.7 | 59. 68 
HED. 22-2228 3 | Feb. 24 3 262 do=s= 1 27 29 | 97.9 | 23.7 | 59.80 
Wian4 2225. 1| Mar. 6 1 23) doses Le ee a eee 16 18 | 97.9 | 28.0 | 64. 65 
Mar. 62-22. 1| Mar. 7 1 de Mar 28) |e one = 1 21. 22 | 97.9 | 34.0 | 64.32 
RPAT Sf 288 1| Mar. 8 1 [es dos s=2 Pye we de 20 21 | 97.9 | 34.0 | 63.77 
1917 1917 1917 
Loi Bia eases 1| Feb. 3 1 3 | Mar. 13 Tela Sa 38 41 | 93.0] 9.5] 50.92 
Hebetga2 2 2} Feb. 17 2 4 Mar. 20 1 1 31 35 | 93.0 | 25.0 | 56. 22 
Mar. 10--___- 1 | Mar. 11 1 1 | Mar. 31 AE ess Sa 20 21 | 87.5 | 32.0 | 63.31 
1918 1918 1918 
anev20s_ 22 2} Jan. 25 2 5 | Mar. 11 2) eae 45 50 | 97.5 | 33.5 | 49.46 
Vaneol. =. 2| Feb. 6 2 6 Mar. 13 1 1 35 41 | 97.5 | 12.5 | 53.86 
1920 1920 1920 
LE es ae 1| Jan. 8 1 2 | Mar. 18 nD fee aca oe 70 72 | 81.0] 19.0 | 48. 67 
Lavy (ees Seas 1| Jan. 18 1 Lee Ole beeen 1 60 71 | 81.0] 19.0 | 48. 83 
(20 0 eee 1} Jan. 16 1 7 Mars 2o0| ees 1 69 76 | 81.0! 19.0} 51.31 
HebG2=.5 2 1] Feb. 9 1 Bie 2nd Opp Ae eos QE) 45 48 | 81.0 | 19.0 | 52.46 
Keb: 18-2. .-.- 1 | Feb. 20 1 A WIM IBS Barf Meee 1 36 38 | 81.0 | 19.0 | 54.08 
HeD2ose 1| Mar. 1 1 > | Wee. 74) | oe ee 1 24 31 | 81.0 | 19.0 | 52.61 
1921 1921 1921 
Liab eee 1} Jan. 15 1 4 | Mar. 1 | See a 45 49 | 83.0 | 26.0 | 52.03 
(ee 1} Jan. 17 1 6 Ware Sian 1 45 51 | 83.0 | 26.0 | 52. 44 
clits 28 Ft 38 1} Jan. 29 1 1 Mar. 12 Pp [tees = 42 43 | 83.0 | 27.0 | 54.91 
Hep 5 eo be 2] Feb. 7 2 2 | Mar. 15 1 1 36 38 | 83.0 | 28.0 | 56.89 
HehyG20 ook. 1] Feb. 8 1 2Py pe doza = 1 | (ate ee 35 37 | 83.0 | 28.0 | 56. 94 
es ae 1] Feb. 10 1 Aire doses 1 I (pee re 33 37 | 83.0 | 28.0 | 56. 94 
Mebnigo2.2 22 2| Feb. 14 2 1 Mar. 16 1 1 30 31 | 83.0 | 28.0 | 58.90 
58252 °—26——_5 
