40 OYSTER-SHELL BAEK-LOUSE. 



was known to exist, and was thought by some to be on the in- 

 crease in that section of the country. And, furthermore, it ap- 

 pears from the correspondence of the American Entomologist, that 

 this insect has been found even so far south as the State of Missis- 

 sippi. The question therefore arises, with considerable pertinency, 

 whether this destructive insect may not be disappearing from the 

 north, only to enter upon a new career in the mure southern lati- 

 tudes. All I can say in answer to this question is, that this has 

 always been regarded as an essentially northern species, and, there- 

 fore, it is supposed that it will not multiply to any great extent at 

 the South. A little circumstance, incidentally mentioned by Mr. 

 Walsh, gives us additional encouragement. Re states, in a note 

 to his report, that he received some branches infested with this in- 

 sect from Mr. Huggins, of Macoupin county, and that upon exam- 

 ining them he found that in nineteen-twentieths of them the con- 

 tents of the scales had been destroyed, as he supposed, by Acari, 

 It is not necessary here to go into a detailed account of the vari- 

 ous remedies that have been resorted to for the purpose of destroy- 

 ing this insect. Mr. "Walsh instituted a thorough series of experi- 

 ments in this matter, and has given us the results in his treatise 

 upon the Oyster-shell Bark-louse, in his first report. To that I 

 refer those who are interested to know the past history of the 

 treatment of this pest. The essential and universally approved 

 remedies can be stated in a few words. The treatment is of two 

 kinds : that which is appropriate on or about the first of June, 

 when the lice are young and tender, and that which may be ap- 

 plied at any time in the winter or early spring, with a view of 

 destroying the eggs under their protecting scales. At the former 

 period, much weaker applications, of course, are successful than 

 in the latter, and we are necessarily restricted to such on account 

 of the danger of injuring the young foliage. Yarious kinds of 

 narcotic and alkaline washes have been tried for the purpose of 

 destroying the lice in their incipient stages, but the most effectual 

 of all is common soap-suds. This has to be used of different de- 

 grees of strength, according to the part of the tree to which it is 

 applied. Undiluted soft-soap can be applied to the trunk of a 

 tree of considerable size, without injury ; on the smaller branches 

 it is better to dilute it to the extent of from four to six parts of 

 water to one of soap ; and on the young shoots and foliage it must 

 be very largely diluted, not exceeding two or three cups of soap 



