HARD WICKE 'S SCIENCE - G OS SI P. 



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It does not always assume the position drawn, but 

 lengthens itself out in the act of feeding. 



The best and most elaborate account of the beetle 

 is contained in a little work called "Potato Pests," 

 published by the well-known Orange Judd Company, 

 of New York, and written by our countryman Mr. 

 C. V. Riley, the State entomologist of Missouri, to 

 whose various reports all English writers on the sub- 

 ject are indebted. As this is not accessible to all, it 

 maybe mentioned that there is a good and illustrated 

 account by Mr. H. W. Bates, in vol. xi. (second 

 series) of the "Journal of the Royal Agricultural 

 Society of England," 1875, pp. 36i--375- 



Space will not permit an extended notice in these 

 columns ; but the following may be given as a sketch 

 of the progress of the beetle since its discovery. It 

 was known to occur on a sand-bur or wild potato 

 {Solamtm rostratian) in the Rocky ^Mountains since 

 1820, or thereabouts. As the cultivated potato ex- 

 tended westwards, it acquired a preference for that 

 plant, and spread eastward, until, in 1859, it was in 

 Nebraska, in 1 861 in Iowa, in 1864 and 1865 in 

 Illinois, on at least five different points, in 1866 in 

 Wisconsin, in 1868 in the centre of Indiana, and so 

 on further eastward to the Atlantic, until it touched 

 the seaboard at many different places in 1874, having 

 travelled at an average annual rate of about eighty- 

 eight miles. Having reached New York, it swarmed 

 and extended nortli and south along the coast, and 

 finally reached Canada, having spread over an area of 

 nearly 1,500,000 square miles, — considerably more 

 than one-third the area of the United States, and now 

 occupying more or less completely thirty-four states 

 and territories, besides a large portion of Canada. 

 Its western barrier appears to be the Rocky Moun- 

 tains, and the Atlantic would, of course, prove an 

 effectual limit to the east were it not for ships in the 

 harbours, on which it has swarmed since 1874 to an 

 incredible extent, even floating on the sea in vast 

 numbers far from the shore. The wonder, therefore, 

 is, not so much that the insect should succeed in 

 reaching us on board ship, but that it should not long 

 before this have done so, and in great numbers. 

 There is no need for any material connected with the 

 potato or its cultivation to be shipped in order to 

 afford a cover for the beetle, which is ubiquitous on 

 the American side, and can as easily be brought over 

 en masse in a hat-box or secreted in unused clothing, 

 as in a barrel of potato-haulm. 



But whether, having arrived, it can succeed in 

 becoming acclimatized in England, is another matter, 

 upon which opinions are divided ; though there would 

 seem great danger of its effecting a lodgment in 

 Southern Europe. To the writer, it seems that our 

 much damper and colder climate, not affording op- 

 portunities for the rapid succession of broods which 

 the insect develops in America, must materially mili- 

 tate against its obtaining a permanent hold ; and the 

 collateral argrmients that no American beetle has 



ever established itself in England, and that we possess 

 no near ally of this particular one (the original home 

 of whose special generic group appears to be almost 

 tropical, in Central America), cannot fail to have 

 some weight in the matter. 



But the powers of exceptional vitality and exten- 

 sion of range possessed by the Colorado beetle are 

 so great, that it would, even if all these objections 

 were granted, be the height of folly to neglect all 

 possible precautions against its encroachment ; and 

 of these the first is a dissemination of a knowledge of 

 the foe. This has already been done to a large extent, 

 both by the Government (according to its lights) and 

 by private enterprise ; and on this point it is some- 

 what amusing to find a paper like the Standard 

 suggesting the publication and dispersal of drawings 

 of the insect as a likely means of imparting know- 

 ledge, long after that course had been very exten- 

 sively adopted. There are penal clauses in the 

 Destructive Insects Bill above referred to against 

 harbouring the beetle, or selling it, or offering it for 

 sale alive, which seem to suspect its systematic intro- 

 duction by naturalists, and with that idea would also 

 seem opposed to the most certain method of obtaining 

 accurate knowledge of the insect. It can scarcely be 

 believed that entomologists would be so culpably 

 careless as to permit the escape of living specimens ; 

 and it is to be hoped that no coleopterist will import 

 the "Bogus potato-bug," DorypJiora jimcta, not in- 

 cluded in the Act, but specifically very close to the 

 Colorado beetle, for the purpose of puzzling the Go- 

 vernment officials charged with the levying of the 

 pains and penalties warranted by it. 



Should the beetle by any evil chance obtain a foot- 

 ing in our fields, the method employed at MUlheim, 

 as detailed in the Cologne Gazette, will prove most 

 effective for its destruction: this, briefly, consists of 

 isolation of the infested locality by ditches, and 

 covering its surface with sawdust which is saturated 

 with benzoyl, benzoyl also being poured into the 

 ditches. After burning the surface, it is ploughed in 

 close ridges, again saturated, and again burnt. When 

 once the beetle has fairly settled itself over too large 

 an area for such vigorous treatment, the best course 

 appears to be, to take especial and energetic pains in 

 systematically hunting for it in spring, before the 

 parents have deposited their eggs. As a destructive 

 dressing, the Americans find that a solution of Paris 

 green in water, sprinkled by a machine over the plants, 

 is the most effectual. 



Of the various natural enemies to the beetle (chiefly 

 other insects) occurring in America, it would be 

 practically useless to speak, as they cannot well be 

 found here, though, doubtless, some of our own pre- 

 daceous and parasitic species (and also our insectivo- 

 rous birds) would have something to say to the 

 invader. The parasitic mite which has figured in 

 various London papers (roughly copied from Riley's 

 drawing of Uropoda ainericana), has, however, a 



