C. L. Walton 
227 
During the very worst periods it seems that isolated cases occur 
about even the very highest parts of the Area. 
An old sheep farmer of great experience put it thus: “ They (the 
maggot flies) go up and down the mountain (Plynlymon) just like the 
thermometer/’ a better simile would be hard to find, since it is the 
rise and fall of temperature that governs the activities of the flies. 
It was quite usual during the late summer and autumn of 1914, to 
observe a considerable proportion of ewes and lambs in the lowland 
fields with either “broken fleeces” or with patches sewn on to the wool. 
Shepherds state that sheep that have been travelled or hard driven, 
and so heated, are very liable to attack, the fly being probably attracted 
by strong odour. I have examined a number of the farms that com¬ 
plained of severe outbreaks and made enquiries and observations on 
others that were unusually free and elicited a good deal of information 
particularly with regard to dipping. This is a vexed question and is 
locally the subject of perennial and vigorous discussion; the whole 
matter is affected by sheep scab and compulsory dipping times. For 
dipping purposes Cardiganshire has been divided into two areas, a 
northern and a southern; the line between the two starts from the 
centre of Aberystwyth and follows the main road to Pont Erwyd; 
thence it is continued up the river Rheidcl to the county boundary. 
North and west of this line it is compulsory to dip between September 1st 
and November 15th, and south of it between July 15th and August 31st. 
These dates are arranged to combat sheep scab and on account of 
them, earlier dipping against maggots is often not undertaken. Some 
farmers wait until the compulsory period before dipping at all meanwhile 
merely treating “struck” sheep with solutions of dip from a bottle; 
these men have usually the greatest trouble and losses. Others adopt 
the protective method of dipping before the compulsory time, but still 
too late; and only comparatively few dip about the commencement 
of the danger period; these few, even when in a bad district seldom 
have serious cause for complaint especially if careful supervision is 
exercised between dippings. There are a few farmers who dip as often as 
three or four times, commencing in June, but the average time appears 
to be July, and late in the month rather than early. The idea of dipping 
against maggots seems to have been obscured in this Area by the trouble 
with sheep scab, which pest has now, fortunately, been controlled. 
Several makes of dip are in use in the Area, and having regard to 
the often irregular and unsatisfactory manner of use it is difficult to 
criticise their relative values. All kill maggots satisfactorily, but there 
