gt tte te 
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N45 
Washington, D. C. 
THE CATTLE GRUBS OR OX WARBLES, THEIR BIOLOGIES 
AND SUGGESTIONS FOR CONTROL 
By F. C. BisHopp, Entomologist, E. W. LAAKE, Associate Entomologist, and 4 
H. M. BRUNDRETT, Assistant Entomologist, and R. W. WELLS, Entomologist, 
Investigations of Insects Affecting the Health of Animals, Bureau of Ento- 
mology 
CONTENTS 
Page Page 
ETERS Tih Tey zea aE as Ee 2 | Development and habits___________ 41 
Life history in brief______________ 6 | Seasonal history -~-22 === 74 
Distribution= 2 ee ee ahs 6 | Natural control ________ Sree a sae vs) 
Economic importance______________ 11 | Artificial control _______ os 85 
TSO 508 0 ae 0S ee ce 17 | Possibilities of eradication | by sys- 
Common names and popular ideas__ 19 tematic destruction of grubs_____ 108 
PET OS ibs tins set Ne Se 20 | Legislation on grub control________ 110 
Actions of cattle when attacked by SU Tn AUT See Sec Se ee ee 110 
adult Hypoderma_______________ Zee awitorature -Citeds: 425 are es ee 114 
Description of stages_______--____ 26 
How the larve of Hypoderma line- 
atum gain entrance to the host___ 33 
The cattle grubs (Hypoderma lineatum De Villers and H. bovis Coe A 
De Geer *) are among the most widespread and injurious insects with 
which our livestock are beset. Nearly every owner of cattle is 
familiar with these larve, which are found under the skin on the 
backs of cattle in the early spring. Few, however, connect them 
with the adult insects which are known as heel flies or warble flies. 
Still fewer people have ever seen a heel fly, and many stockmen say, 
“‘T have heard all of my life of the heel fly and have seen the cattle 
run from it but I have never seen one.” This has led many to regard 
the fly with something akin to superstition or to consider ts exist- 
ence a myth. 
Among scientific workers there is also a very meager iihcheiedee 
of the true life history or importance of these insects. Although a 
considerable number of veterinarians, zoologists, and entomologists 
have made observations and published articles, much of this work 
has been of a fragmentary character and most of the important bio- 
logical facts have been established during the last decade. It is the 
writers’ desire to set forth briefly the knowledge gleaned to date, and 
especially to present facts yet unpublished regarding the life his- 
1Resigned July 24, 1928. 2Order Diptera, family Oestridae. 
58252 °—26——_1 
