160 uRoeit lioMopTUiA. 



•IfVtMiDIU from thb inject : the )<>unff liavt><« uf the flnt product curlnj, thickrmd, 

 |«T**in* red ur bniwu, and uiM»t uf them |m ridu-d The trc«-9 aflrrKurds |>ut f'-rth n new 

 crup uf leave;!, and all .Htirvlvi-d, tbuugh the fruit wus destrujed In the Idussoui. ( Kor a 

 delineatiuu ff the jicachtrre aphiit, Mt' riatr xxix, fiR. 7.) 



It b evident IVocu the foreguiug remark.^, that plunt-lice arc injuriuu.*, buth through the 

 wuundn they Inflict u|n<u the port!) uf the phuit they inhabit, and fn^ui the fluids or uu- 

 (riiutnt they aUtraet from the circulation. A^ u fimily, their luibiLi are the MUie. I>ut 

 Bonie species ur kiuds ap)>ear t<i U* ni<>re injurious than others ; and it M-euis dillicult to 

 account for all the effect!* they prlTluce, unless they [.ossess u |>oi!>ouou^ principle, lu 

 »U]>port of this obiiervation, I may Mate that the pear i!>iufeslc«l uith a kind that kilU the 

 tri-e when young. Uf this fact, I wa.s informeil l>y Dr. <Jvii> I'limb of Salisbury (Conmcti- 

 cut) : tlie limbs or twigs which he showed me were bruwn and dry in patches. Afterward* 

 Mr. Hakrih of Cambridge investigated the matter, the re!>ultjt of uhirh he luis rommuni- 

 cate.l in his work on insects injurious to vegetation. Dr. iVi mu, who w;u» the !ir>t to notice 

 thcie minute parasites of the i>e;ir-trce, entert'd with much zeal and spirit into the In- 

 vestigation of their ert'ect.i, and t>f the remedies to de^troy them. 



Tlie genus t«> which this insect belongs is Psvll.^, one of the jumping plant-lice, but 

 destitute of the cutton-like covering. From the observations of Dr. I'limb, it apjKars to 

 give birth to two or more broods during the year, being found uiK>n the i>ear from May 

 to OctoUr. They tlrst a[>|>eared iipon imjxjrted trees. My own trees, which were obtaintd 

 from Rochester, ajid were also im)N>rte<l, had many liinl>s that npixared rusty and drj- ; 

 and though thes4' limbs wen- lost, the trtes survived. The npjH-arances of the linil)S were 

 similar to thi>se of the branches preservetl by Dr. Pli.mb; but 1 was unable to find the 

 aphis, although I sought for it lUligently. 



This insect i.* descrilH;<l as of a didl orange color, and one-tenth of an inch b-ng when 

 perfect : the thorax is brownish orange. The female Is more pointttl behind than the male. 

 According to Mr. Harris, it may pn>ve to be the PryHa yyri of KurojH'. \\ may be well 

 to remark, that when the bnuiches of a pear-tree bec«-»me dark and dry in i>atches, it is 

 advisable to s«'arcl» for this insect. The remedies recomniende<l are, first, rubbing otT the 

 lice with a brush. Mr. 1I.\hris advises the application of string sapsuds with sulphur, 

 by means of a brush, belure the buds c\{>Mnd : so also the use of whale-oil s«ai|i'. 



The insects of the Genus Tubips, likewis*- beloiuiiug to the Family ApiiioiDi:, are also 

 It^urious. Their wing«, instead of lying obliquely upon their backs as in the Genus Aruis, 

 He flat, and arc fringed. They are supp<^>sed to |x>ison plants by their puncture, producing 

 thereby curls and a thickening of the tissues of the leaf. They may be treatetl with soap 

 and water, or whale-oil soap dissolved in water : a strong decoction of tansy may serve. 



* HiBiit 00 Intecti iT^urlnoi to Trgelttloo, p. 90S. 



