870 HENRY SHIMER, M. D. 



not so abundant on the bark, traveling around, as during the fine sun- 

 ny days just passed. They are mostly remaining quiet under the scales, 

 but here and there one may be seen on the bark, although it is quite 

 cool for insect comfort. The careful observer will not confound this 

 Acarus with another yellowish-white mite-like insect, that I find here 

 on the bark of the trees; this runs much more rapidly than my Aca- 

 rus ; its body is, in proportion to its size, much longer, as it appears 

 under my exploring glass. What more might be determined of its 

 habits by careful observation, although very interesting, I have not 

 taken the time to do, neither have I made a microscopic examination, 

 I dont find it under any of this year's scales, therefore I do not believe 

 that it is an egg-eater, like my Acarus ; it may be a vegetable feeder, 

 or possibly feeding on the decomposing matter of the scales of former 

 years. • 



I raised up a great number of the new, this year's — scales, for they 

 are easily distinguished from the old, last year's, scales — and T found 

 that in nine-tenths of them, all, or nearly all, the eggs were destroyed; 

 they are all shriveled skins of a ferruginous color. Of the remainder, 

 only a few, perhaps one-hundredth of this year's scale, are in the pos- 

 session of all perfect eggs. In the others^ at least one-hulf of the eggs 

 have been destroyed where I conducted my observations; regarding 

 this, I am not able to speak of many different localities. 



I have no doubt that the Pomologist, who has not already seen this 

 Acarus, will hail its discovery with great joy ; for in this insect I be- 

 hold the most, and indeed the only efficient, insect-enemy of the Apple 

 Bark-louse that I have been able to discover, during the entire course 

 of my investigations. From my observations it can be seen that, al- 

 though it may not entirely exterminate the iVpple Bark-louse, yet it is 

 exerting a wholesome, restraining influence, doing much more than 

 man could do, without great trouble and expense, with a thousand 

 washes — an unobserved microscopic object of deep interest. 



Of methods for destroying the Bark-lice, I observed that, when they 

 are just hatched, a strong, common, soft soap-suds is as effectual as 

 anything; when wet with it, the insect dies in a moment; but after 

 the scale is formed the case is more difficult, and soon the strongest 

 washes will not affect them. A hint to the wise is sufficient — watch 

 for the hatching of the young Bark-lice a few days after the appear- 

 ance of the blossom. This year here it occurred about ten days after. 



Mt. Carroll, 111., November 1, 18G7. 



