332 MR HAHUy ON INSECTS 



naturalist, lias devoted attention to these neglected creatures, I need only 

 refer to the r.avnj^cs of the scale insects, a nearly allied rucc, on the sugar 

 t'ano and cocoa nut tree in the West indies ; to iliose wliicli have destroyed 

 the lertiiity of the orange groves of the Azores, whereby the inhabitants 

 are deprived of their usual means of subsistence and comfort ; or to those at 

 present desolating the coffee plantations of Ceylon, for wliieh there is no 

 apparent remedy but in consigning the infected trees to the dames. To 

 the rigour of our northern clime, which determines the life of the plant as 

 well as of the insect that it nourishes, we may look for a more plausible 

 reason why the noxious insects of one year seldom re-appear in suftident 

 numbers to create alarm during that which succeeds. It thus happens that, 

 although we cannot boast of the exquisite productions of a milder sky, we 

 have yet, in this, as in many other respects, under the blessing of a good 

 ProvidencOi an adequate compensation. 



SUPPLEMENTARY NOTES. 



NOTE A. 



ON THE TORNIP WEEVIL, CMIB-ROOT, AND FINOERS-AND-TOES, 



In treating of the disease termed fingers-and-toes, I have stated the gene- 

 rally received opinion. The conclusion at which I have myself arrived, 

 from several observations made since the first part of this paper was writ- 

 ten, is not quite favourable to the insect theory. After two years' exam- 

 ination of turnips in the autumn, t have failed in detecting the larv;o of 

 weevils in any portion of the diseased bulbs ; and, even at the commencement 

 of the disease in spring, I have seen no trace of thom. I have, however, 

 several times, found a larva enclosed in a gall on the yellow turnip ; but it 

 had only occasioned a slight globular elevation on the surface, about the 

 size of a pea. This appears to be the " yellowish maggot " referred to by 

 Mr G. W. Johnson, in the Quarterhj Journal of Agriculture, viii., 317, as the 

 product of a C///h'/>.9 ; and he states that turnips aifected with it are "sup- 

 posed to decay earlier than others, fr>m the hollow left by the insect allow- 

 ing the access of air, mois^ture, and putrefaction.-' The first statenunt 

 appears to rest merely on conjecture; and, indeed, the same author else- 

 where {Gard. Miff., Dec. 1828, p. 451,) ascribes clul^root among the Brassi- 

 cte, to an eff'ort of the plant, similar to that which occasions some grasses 

 to become bulbous-rooted in dry soils, to retrieve deficient perspiration of 

 the foliage during droughts. The grub in question is that of one of the 

 Ctirculiomda:, or w*eevils. It is slug-like, footless, thickest about the middle, 

 rather convex above, yellowish white, shining, soft, lubricous, sliglitly 

 slimy, with numerous undulated wriidi.Ies above, tlie intestinal canal ap- 

 pearing through the integument, dusky or brownish; tl>e sides, with an ill 

 defined divi.sion line, minutely tubtrindated; the separate segments there 

 most distinct : belly scarcely less wrinkled, bui flatter than the back, a brown- 

 ish »pot on the breast, and another near the anus; head corneous, small, 

 rotuiidate-quadratc, with two converging depressions in frunt, and a suidv 

 longitudinal line on the crown, light testaceous, front and mouth brown, tip 

 of the jaws deeper tinted; eyes minute, black. Length, l-i to 2 lines. It 

 moves by applying its head to the object, and dragging itself onward by 

 the verniicular contraction of its body, assi.ated by the 'wrinkles of its 

 under side. When old it has a greater disposition to proceed in a circle 

 than straight forward; whence the shape of its gall may be, in some re- 

 spects, the rebult of its lolatiun. It frequently rolls itself over to a di."?- 



