TRIFID.S. 311 



damage and risk in an important branch of manufacture — 

 that of linen. A necessary process in this manufacture — 

 that of bleaching — is carried on in the north of Ireland by 

 spreading the linen, in the daytime, on the grassy hill-sides 

 in the open air ; and in addition to the material manufactured 

 in that country large quantities are sent over from Lanca- 

 shire to be bleached in this purer, cleaner atmosphere. So 

 important is this process that it is carried on as a business 

 separate from the actual manufacture of linen, extensive 

 premises being set apart, and much capital invested in it. 

 From time to time, for many years — usually in isolated years, 

 however — complaints have been made of damage caused to 

 the linen, when bleaching, by caterpillars, which were 

 asserted to eat holes in it to such an extent as to render 

 considerable lengths nearly worthless. In the year 1888 the 

 Eev. W. F. Johnson, then living at Armagh, wrote to me that 

 the mischief had re-commenced, and at my request sent over 

 a number of larvsG which had been actually picked off the 

 damaged fabric. The majority of these larvee proved to 

 belong to the present species. Arrangements were soon 

 made, by one of the firms afEected, to carry on certain 

 suggested experiments, and it was soon ascertained, definitely, 

 that the damage did not take place while the linen was lying 

 upon the grass, but that many larva3 availed themselves of 

 the covering, crawling upon the underside of it, so that they 

 were taken up with it when the linen was brought in^loors in 

 the afternoon. It also appeared that if the fabric was at 

 once placed in what is denominated the "dip," a weak 

 solution of chloride of lime, no mischief was done ; but that 

 any pieces of linen which remained heaped together as 

 brought in, through the night, were seriously damaged. 

 LarvEe were then wrapped up, purposely, in small pieces of 

 linen and placed under some small degree of pressure, with 

 the result that many of them gnawed their way through, and 

 made holes precisely as in the damaged pieces. 



So far as could be ascertained, all these belonged to the 



