1889.] 221 



The larvae sent were of three of our commonest species of Noctuce, 

 and of two species of sawflies — that of Sp. fuliginosa does not appear 

 to have been noticed at all. The sawfly larvae I am unable to deter- 

 mine, but as it was proved that they did no damage, but only crawled 

 upon the liuen, they may be dismissed from notice. The Noctuce 

 were Triphcena pronuba, T. orbona, and Agrotis exclamationis, all young, 

 most of them from one-fourth to one-third grown, the last-named 

 species being in the large majority. 



The linen is laid out on the grass for, I believe, some days or 

 weeks to bleach, and it has always been supposed that the damage 

 was done while lying on the grass, and the only motive that could 

 reasonably be suggested was that the larvae were impatient of con- 

 finement, and gnawed their way through the linen at night for the 

 sake of fresh air. This view proved to be a mistaken one, but I will 

 quote Mr. Ewart's own words. On the 22nd ult., he wrote me as 

 follows : — " "We have found that the damage is not done on the grass, 

 but after the cloth comes off the grass, when lying in heaps before 

 being put into the next process, which is technically termed ' dip,' 

 i. e., a weak solution of chloride of lime. This was discovered thus : 

 when a parcel of cloth was brought in from the field, it was at once 

 examined, piece by piece, until stopping time came at six o'clock, and 

 what had not been examined then lay over until the next day, when 

 quite a number of pieces were found to be damaged, all that had 

 been examined the previous day having been free. We have experi- 

 mented with the different varieties of grubs by folding each in a 

 small piece of linen, and putting some weight on the top of them, as 

 there is considerable weight on the cloth when in heaps. 



" The brown grub, of which I sent you specimens to-day, is the 

 only one which cut holes, and it certainly did so, just the same as the 

 original damages. Thus, it would appear likely that if the linen is 

 put into the next process on the same day that it is lifted from the 

 grass, there will be no damage, and this is quite practicable. If the 

 cloth is lifted on a wet day, the custom is to keep it on the racks till 

 it drains, but we should simply have to leave it out on the grass till 

 it was sufficiently dry. Of course, in wet weather, this would involve 

 the loss of a day or two, but that is a small premium to pay for 

 immunity from damage. 



" It is rather a strange thing that some of these grubs, after 

 being all night in the dip, are alive next morning when brought' out ; 

 and, in fact, on being subjected to a further immersion for another 

 ten hours they are nothing the worse." 



