REPORT OF THE SOCIETY 33 



about the middle of April and continues to annoy cattle until the middle of May. 

 On the other hand, bovis is to be observed for the first time at the begininng of 

 June, and specimens have been captured by Hadwen as late as July 25th, whilst 

 cattle have been noted a few days afterwards behaving as if tormented with this 

 species. 



It will be thus seen that as regards their adult activities and seasonal appear- 

 ance, the two species are mutually exclusive, and it is very improbable that they 

 will be both present among a herd of cattle at the same time. 



The comparatively early appearance of lineatum has an important bearing 

 in relation to the undertaking of prophylactic measures, and this combined with 

 the more inoffensive behaviour of this species has probably been responsible for 

 the fact that the application of special dressings on cattle has been made too late 

 to be of any avail in reducing the intensity of egg-infestation. 



Oviposition. 



The attacks which the flies make on the cattle are for the purpose of deposit- 

 ing their eggs on the hair. The method employed by lineatum is much more un- 

 obstrusive and gentle than that of hovis. In a rapid, blundering fashion, hovis 

 selects the animal v/hich it intends to 'strike,' and with its telescopic ovipositor 

 extended makes a headlong, speedy flight at its host. The double valved ovi- 

 positor slides down the particular hair chosen and the egg is rapidly extruded and 

 left behind at the base of the hair in close proximity to the skin. There it is 

 firmly fixed by the clasping flanges of the pedicel, the attachment being more 

 firmly secured by the presence of a gluey substance secreted at the time of egg- 

 laying. 



In contrast to these methods are those of lineatum, which generally prose- 

 cutes its business of ovipositing when the cattle are in a recumbent position. 

 It may then be observed according to Hadwen^ (p. 4) to run backwards along the 

 ground in approaching its host, and pushing its ovipositor among the hairs, leaves 

 its egg behind. Several eggs may be laid on a single hair, whereas hovis usually 

 lays but one per hair. The animals show some annoyance and irritation when 

 lineatum attacks them as they are standing, but they do not generally stampede 

 in such abject terror as hovis with its more clumsy methods inspires. 



Remedial Measures. 



Warble-flies may be attacked in three different ways as follows: 



(1) Prevention of egg-laying. 



(2) Destruction of eggs and newly emerged grubs. 



