THK COLORADO BRKTLE. 219 



once. If let go free that one beetle may be just tbe starting- 

 point of a countless horde. They are easily distinguishable 

 by their ten black stripes and orange colour ; and all such 

 beetles should be destroyed. 



Presently — next season, it is to be feared, if not the present 

 one — the eggs should be looked for on the young shoots and 

 beneath the potato leaves, and all that are accessible, as well 

 as the orange larvae, should be picked off and destroyed at 

 once; but on a large scale all are not accessible, and then is 

 the time to be prepared with the only application which 

 hitherto has been found thoroughly to keep the larvae in 

 check. This dressing, which is simply a solution of Paris 

 green (arsenile of copper) sprinkled over the infested plants, 

 is easy of application ; the proportion used is three table- 

 spooniuls of green mixed with half a bucket of water first, 

 and run through a funnel-shaped strainer into about two 

 more buckelfuls of water. This quantity is put into a tin can, 

 with two india-rubber tubes at the bottom, each with a rose 

 at the end, and a simple lever apparatus inside shuts off the 

 supply when wished. With this tin can — of which the details 

 are given more fully in agricultural reports — fastened on his 

 back, one labourer can sprinkle five to eight acres a day ; 

 and no evil results have been found to follow from the 

 arsenic. A pound, or somewhat more, is sufficient for one 

 acre ; and the only precaution requisite seems keeping the 

 tin specially for that purpose, and insisting on care with 

 regard to the green that might be left about or adhering to 

 the labourer. As a dangerous poison, it requires great 

 attention in the using ; but it appears in no way to make the 

 potatoes prejudicial to health, and to be a certain means of 

 keeping the larvae in check. 



Whilst the present excitement lasts, the Doryophora is not 

 likely to make good its settlement generally ; but the great 

 danger lies in the neglected nooks to which its wings may 

 convey it, but to which a knowledge of its appearance and 

 destructive powers will not so soon penetrate. There, as with 

 many of our destructive insects, will be the places from 

 which, once established, it will reappear perpetually ; and 

 the entomologist who will spread the requisite knowledge of 

 its appearance, and the means of prevention, in his own 

 district, will be doing most important service, and carrying 



