﻿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 debris, such as straw 

 and broken leaves, but they do' not burrow into compact soil or sand 

 to any extent. The larvae 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 

 tiie case of 238 larvae of H. lin-eatum was 3.4 days. Kepresentative 

 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 larvae 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 larvse 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. Eepresenta- 

 tive data are given in Table 8. 



T-4BLE 8.- 



-Duraiion of prepupal and pupal stages of Hijpodcrma Uneaium at 

 Dallas, Tex. 



L^rvv emerged 

 from host 



Pupated 



Pre- 

 pupal 

 period 



Flies emerged 



Pupal 

 period 



Period 

 from 

 drop- 

 ping 



to 

 adult 



Temperature 

 dropping to adult 



Date 



>Tum- 

 ber 



Date 



Num- 

 ber 



Date 



Num- 

 ber of 

 males 



Num- 

 ber of 



fe- 

 males 



Max. 



Min. 



Aver- 

 age 

 daily- 

 mean 



1916 



Feb. 17 



Feb. 18 



Feb. 21 



Do 



Feb. 22 



Mar. 4 .... 



Mar. 6 



Mar. 7 



1917 



Jan. 31. 



Feb. 13 



Mar. 10 



1918 



Jan. 20 



Jan. 31 



1920 



Jan. 6 



Jan. 7 



Jan. 9 



Feb. 6 



Feb. 18 



Feb. 23 



1921 



Jan. U 



Do 



Jan. 28 



Feb. 5... 



Feb. 6... 



Do 



Feb. 13 



1 

 1 

 1 

 1 

 3 

 1 

 1 

 1 



1 

 2 

 1 



2 

 2 



1 



1 

 1 

 1 

 1 



1 



1 



1 

 1 

 2 

 1 



1 

 2 



1916 

 Feb. 21 



---do 



Feb. 22 

 Feb. 23 

 Feb. 24 

 Mar. 6 

 Mar. 7 

 Mar. 8 



1917 

 Feb. 3 

 Feb. 17 

 Mar. 11 



1918 

 Jan. 25 

 Feb. 6 



1920 

 Jan. 8 

 Jan. 18 

 Jan. 16 

 Feb. 9 

 Feb. 20 

 Mar. 1 



1921 

 Jan. 15 

 Jan. 17 

 Jan. 29 

 Feb. 7 

 Feb. 8 

 Feb. 10 

 Feb. 14 



1 

 1 

 1 

 1 

 3 

 1 

 1 

 1 



1 

 2 

 1 



2 

 2 



1 

 1 



1 

 1 

 1 



1 



1 

 1 

 1 



2 

 ) 

 1 

 2 



Days 



3 



2 

 2 

 2 

 1 



1 



3 



4 



1 



5 

 6 



2 

 11 

 7 

 3 

 2 

 7 



4 

 6 

 1 

 2 

 2 

 4 

 1 



1916 

 Mar. 21 

 Mar. 20 

 Mar. 21 

 Mar. 22 



—do.... 



...do 



Mar. 28 



-..do 



1917 

 Mar. 13 

 Mar. 20 

 Mar. 31 



1918 

 Mar. 11 

 Mar. 13 



1920 

 Mar. 18 



-.do.... 

 Mar. 25 



...do 



Mar. 27 

 Mar. 25 



1921 

 Mar. 1 

 Mar. 3 

 Mar. 12 

 Mar. 15 



...do 



...do 



Mar. 16 



-. 



1 



2 

 1 

 .. 



1 

 1 



1 



2 



1 



1 

 - 



1 



i' 



1 

 1 

 1 

 1 



1 



.. 



1 

 - 



- 



.. 



.. 

 1 



i' 



1 



i' 



i' 



i' 



Days 

 +29 

 28 

 +28 

 28 

 27 

 16 

 21 

 20 



38 

 31 

 20 



45 

 35 



70 

 60 

 69 

 45 

 36 

 24 



45 

 45 

 42 

 30 

 35 

 33 

 30 



Days 

 33 

 31 

 29 

 30 

 29 

 18 

 22 

 21 



41 

 35 

 21 



50 



41 



72 

 71 

 76 

 48 

 38 

 31 



49 

 51 

 43 

 38 

 37 

 37 

 31 



°F. 

 91.5 

 91.5 

 91.5 

 97.9 

 97.9 

 97.9 

 97.9 

 97.9 



93.0 

 93.0 

 87.5 



97.5 

 97.5 



81.0 

 81.0 

 81.0 

 81.0 

 81.0 

 81.0 



8.3.0 

 83. 

 83. 

 83. 

 83.0 

 8:1.0 

 83.0 



°F. 

 23.7 

 23.7 

 23.7 

 23.7 

 23.7 

 28.0 

 34.0 

 34.0 



9.5 

 25.0 

 32.0 



33.5 

 12.5 



19.0 

 19.0 

 19.0 

 19.0 

 19.0 

 19.0 



26.0 

 26. 

 27.0 

 2H. 

 28. 

 28.0 

 28.0 



°F. 



58.26 

 57.71 

 58.94 

 59.68 

 59.80 

 64.65 

 64.32 

 63.77 



50.92 

 56.22 

 63.31 



49.46 

 53.86 



48.67 

 48.83 

 51.31 

 62.46 

 54.08 

 52.61 



52.03 

 52. 44 

 54. 91 

 56. 89 

 66. 94 

 56. 94 

 68.90 



58252°— 20- 



