Reports to the Board of Agriculture. 1 27 



both are apparently European. It may be, however, tliat H. lineata 

 is natural to both Continents." 



The differences between the two species are pointed out later. 



The life-liistory of H. bovis is, I feel sure, not completely known, 

 but that of If. lineatci is, and it is probable that tlie various phases 

 of development are the same in both species. 



The (Estridds to which the Warble Tlies belong are two-winged 

 files or Diptera, which are all parasitic in their larval stage upon and 

 within mammals {H. lineata, (E. ovis, G. equi, etc.) and man 

 (I), iwxialis). 



Damage caused by Ox Warbles. 



The damage caused by these pests is due both to the imagines or 

 adult flies and to their larvae or " bots." The flies, by frightening 

 stock when on the wing and on the look out for a host on which to 

 deposit their eggs, frequently cause loss amongst "in-calf" cows by 

 making them stampede about the fields, as also in other ways. 



The maggots or " bots " living beneath the skin perforate the 

 hide, and so ruin it when present, as they often are, in considerable 

 numbers. They also cause loss to the butcher, who often finds the 

 flesh beneath the " warbled " areas so altered by the inflammation 

 set up by the parasites that the beef in that region is spoiled. This 

 so-called " licked beef" has a straw-coloured, jelly-like appearance 

 in a newly-slaughtered carcase, but it turns to a dirty green in a 

 few hours. 



Lastly the farmer and grazier may suffer direct loss by the actual 

 death of the affected stock, from inflammation set up by the parasites 

 when present in large numbers. 



Life-history of H. linruta. 



The life-history of this species is now well known. 



The fly deposits her eggs upon the haii- of the beast, particularlv 

 on the legs, just above the hoofs, lience a common name for this fly 

 in America, the " heel-fly." but they are also placed elsewhere. The 

 eggs are fastened to the hairs, usually several together. The eg 

 is of a peculiar shape (flg. 22, e), and is about one-twelfth of an inch 

 long ; each egg immediately it is laid Ijy the female is flrndy attached 

 to the hair by a process which clasps the hair. The animal licks 

 the place where these eggs are i)]aced, and the hirva" hatched from 

 them are carried by the tongue into the mouth. 



The maggots pass into the gullet oru3Sophagus and soon penetrate 

 its walls ; tlien they moult their skins, become smooth, and wander 



