THE AMERICAN ENTOMOLOGIST. 



83 



his descriptiou -with our specimens, it not only 

 disagrees gcnerically, as already explained, but 

 neither the size nor the markings will corres- 

 pond at all. 



We consider it, Iherel'ore, (o he sufficiently 

 certain that tlie Apple-root Plant-louse does not 

 belong to the genus (PempJiii/us'), to which all 

 subsequent authors, in deference to Dr. Rich's 

 authority, have hitherto referred it, but to the 

 very distinct genus {Eriosomd) to wliich the 

 notorious Wooly Plant-louse of Europe belongs 

 {Eriosoma laniyera, Hausm.) And here arises 

 a very interesting question : Is our American 

 Ajjple-root Plant-louse identical with tlic Euro- 

 pean Wooly Plant-louse? AVc think that it is 

 not, for the three following reasons: 1st, The 

 descriptions of the latter do not agree very well 

 with our insect. 2d, The European species can 

 not stand a hot climate, but is contiued to Bel- 

 gium, the north of France, Germany and Eng- 

 land; whereas our species thrives and flourishes 

 best in a hot southern latitude. 3d, The Euro- 

 pean species exclusively infests the trunk and 

 branches of the apple-tree, and it is recorded 

 that Sir Joseph Banks " long ago extirpated it 

 from liis own apple-trees by the simple method 

 of taking off all the rugged and dead old bark, 

 and then scrubbing the trunk and branches 

 with a hard brush" (Kirby and Spence, letter 

 6) ; whereas our American Koot-louse normally 

 inhabits the roots, and is only occasionally and 

 in small numbers found upon the trunk and 

 branches, so that scrubbing and scraping the 

 bark would have little or no effect towards ex- 

 tirpating it. 



It has been said by several authors that the 

 true Wooly Plant-louse of Europe exists in the 

 Eastern States. We incline to believe that this is 

 a mistake, and that in every such case the few 

 individuals of our American Root-louse, that are 

 often found upon the trunk and brandies and 

 suckers, have been mistaken for the transatlan- 

 tic species. Mr. Buel, upon whose statements 

 Dr. Harris chiefly relied to prove the existence 

 of the Wooly Plant-louse in New England, ex- 

 pressly says that " numbers of the insects har- 

 bored on the roots."' (Harris, Inj. Ins., p. 244.) 

 Dr. Fitch describes the Wooly Plant-louse as 

 " situated uear the root, particularly around the 

 base of twigs and suckers growing from the 

 trunk, and where any wound in the bark is 

 healing;"' wliich are the precise localities pre- 

 ferred by our Koot-louse whenever it lives above 

 ground. (Fitch, JSf. Y. Bej)., II, § 17.) And 

 finally Prof. Haldemaii, in an article upon this 

 insect, asserts that it not only attacks " suckers 

 and small branches,"' but also " descends to the 



roots."' (Farm Journal, 18ol, Vol. I, p. 130.) 

 As to the winged specimens, which Mr. A. E. 

 Verrill discovered upon apple-twigs in Connec- 

 ticut in the month of October, they might pos- 

 si])ly have belonged to the exotic species. (Pract. 

 Eniom., I, p. 21.) But as that species is de- 

 scribed as swarming in Europe in such prodigi- 

 ous numbers as to cover whole trees like a coat 

 of cotton, it seems incredible that, if it had been 

 really introduced into such a suitable climate as 

 that of New England, it should not have become 

 a great pest there. Instead of this, however, 

 all authors describe it as occurring above ground 

 in comparatively quite small numbers, wherever 

 it was supposed to exist in the Eastern States. 

 From the enormous rate at which all Plant- 

 lice multiply, it is plain that, if there were no 

 check upon the increase of the Apple-root Plant- 

 louse, it would in a few years' time sweep Away 

 whole orchards, especially in southern latitudes. 

 Luckily for the fruit-growers and fruit-lovers, 

 there exist one at all events, and probably two 

 such checks. The first is a very minute para- 

 sitic fly, which Prof. Ilaldeman figured and de- 

 scribed in 1S51 as infesting in the larva state his 

 supposed AVooly Plant-louse.* The second is a 



CFig. 72.] 



CoI,irs-(.7) ydloivlsli ; {!,) iM nsli-gray ; (c) bn.wn-Wa.-k. 



footless maggot (Fig. 72 «), about J an inch long, 

 which prej'S upon the Root-lice under ground, 

 and changes in the autumn into the pupa state 

 (Fig. 72 b), from which in the following spring 

 there emerges the perfect Fly (Fig. 72 c), which 

 we may call the Root-louse Sy rplius-fly .f We have 



* This Jly bclonss to the Chalcis family in the Or'lci' Ih/mc- 

 r.optcra, aiul was named Eriophihis mail by Prof. HaUlfman. 

 Till' ]i(;m'c and desci-iptiou will bu found in the Farm Jourtuil 

 forl8.)l, pp. 130-1. 



t This is; the same insect referred to in the Annual Report 

 of the .Senior Editor (p. G2), and there sujiposed to prey on 

 the Root-lice and to belong to the Syrphus family, though the 

 perfeet fly whicii he siibseiiuently bred from it was not then 

 known. We subjoin descriptions of this insect in all its 

 stages. 



Tjie UoOT-LoisE SYUpifus-FLY [Pipiza radicum. n. sp.) $ 

 Shinlii'r brown black. Head clothed with short, rather 

 sparse, white hairs, especially the lower part of the anterior 

 orbits and the entire space below the antennae. Jlouth dark 

 rufous. .\-ufcnn:e compressed, with the joints proportioned 

 as a, 2, ."i: joint 3 twice as wide as 1, aud 3 twice as wiile as 

 2; of a diill rufous color, edged above, nan-owly on the in- 

 side, widely on (he outside, with brown black. 'Thornx very 

 finely rugoso-j)unctate, with some short sparse white hairs, 

 especially laterally. Abdomen finely pimctate, with longer 

 white bans, rufo-piceous above on the middle i of joint 1: 

 venter with joint Ipiccous. Leys with all the 6 knees, and 

 in the 4 front legs the entire tibia except a spot on the exte- 



