102 REPORT— 1877. 



Remarks on the Colorado Beetle, and on the Panic existing as to the possibility 

 of its becoming obnoxious in this Country. By R. M'Lachlan, F.R.S. 



The author dealt categorically with the history of the insect, its habits, its 

 migratory movements, and the reason the inhabitants of Europe have had to 

 dread its infliction upon them. The beetle, he said, has existed from time imme- 

 morial in the west of Colorado, on the eastern slopes of the Rocky Mountains. 

 Until eighteen or twenty years ago it was little known except in its native 

 haunts or the cabinets of entomologists. In its home its larvae fed upon one or 

 more species of Solanmn; but when the white man migrated to Colorado he took 

 with him the inevitable potato (another species of Solanmn), which proved ac- 

 ceptable to the beetle, and which afforded it the means of prospering and in- 

 creasing prodigiously. Growing in numbers, the beetles spread over a wider 

 area, and continued their migrations, until, in about fifteen years from the time 

 of the introduction of the potato to them, they had travelled from their native 

 home to the coast of the Atlantic. But even here the insects' journeyings did not 

 cease ; and there is reason to believe that it has bred in Germany, and has been 

 present in its larval state in England. It belongs to the class of Coleopterous insects 

 known as Phytophaga (Vegetable-feeders), which in the larval state live upon the 

 leaves of vegetables. The life-history of the insect is stated thus : — The female 

 lays her eggs on the leaves or other part of the plant above ground. These hatch 

 very soon, and the larvae proceeding from them, after eating voraciously, descend 

 into the earth and form small cavities, in which they turn into pupae. They then 

 remain quiescent till the final change into the perfect beetle takes place. The 

 insect breeds four or five times a year in America; but it is in its larval state 

 that it does nearly all the injury chargeable to it. The perfect beetle is not 

 known to interfere much with the plants, though some say it has attacked tubers 

 during the hibernating period. In Europe attention was not much directed to 

 this formidable farmer's enemy until four or five years ago, when the danger of 

 importation forced people to weigh the disadvantages of a possible scourge, and 

 impelled entomologists to study. Laws were passed in consequence of the agita- 

 tion which then took place, the effect of which was virtually to put in quarantine 

 vessels from America which there was reason to apprehend might bring any of 

 the beetles. In England fear of the insect culminated in the Destructive Insect 

 Bill, passed by Parliament a week or two since. But unless potatoes be imported 

 in the future in far greater quantities and with less care than heretofore, the author 

 believes the danger of their coming concealed among tubers to be very small. It is 

 certain that the beetle swarms on the Atlantic seaboard of the United States, so 

 that there is every chance that it has over and over again been conveyed on 

 steamers and other vessels leaving for Europe. It therefore seems not improbable 

 that a few should have arrived here promiscuously. The opinion expressed in the 

 paper was that the pest is more likely to be introduced in a general manner than 

 from any association with potatoes. 



Neiv Points in the Zoology of Neiv Guinea. By Prof. Rolleston, F.R.S. 



The author commenced by saying that the zoology of New Guinea has had a 

 great deal of research bestowed upon it, and will yet have a great deal more, as a 

 consequence of the profit which has already resulted. A point which recent 

 zoological discoveries in New Guinea throw light upon is, that there was a dry 

 land passage at one time between Australia and New Guinea, recent discoveries 

 in the latter country having revealed the presence there of animals similar to, or 

 identical with, some found in Australia. This is held as proof that where Torres 

 Strait now is there was once dry land. But against this hypothesis is urged the 

 difference between the vegetation of the two islands. This, however, is accounted 

 for by what Herbert Spencer calls the circumambient medium. Though people 

 are inclined to think vegetables considerably less sensitive than animals, sometimes 

 they are more sensitive to heat and dryness ; and the author believes that it is the 



