Abstract
WE think this monograph exceeds in value all others of Prof. Riley's well-known writings on North American injurious insects. The cotton-worm is the larva of a moth of. the family Noctuidœ, and belongs to that section of it in which the caterpillars form what is termed a “half-loop”in walking, owing to one pair of pro-legs Deing absent. It is calculated that in a year of severe visitation it occasions damage to the amount of 30,000,000 dollars, or 151/2 per cent. annual average loss since the war. No wonder it has become a subject of governmental solicitude. The first forty-seven pages are occupied by an exhaustive natural history of the pest, ilustrated by numerous very excellent original woodcuts, and a few (not original) that are indifferent, and also by a fine plate, admirably executed in colours, by what is termed the lithocaustic process. This portion conists not only of a complete history of the moth itself, but also of every imaginable kind of parasite and external enemy, so that it is of the greatest service to the scientific, as well as to the economic entomologist. The formidable nature of the subject may be readily imagined, when it is stated that in the hot districts the number of broods is almost continuous, and that in summer the whole life-cycle may be completed in less than three weeks. As to whether the perfect insect hibernates or not, there appears to be considerable difference of opinion, but Prof. Riley believes it does so in the southern districts, but not otherwise. This biological portion is succeeded by an extended examination of the remedies proved or tried, and an illustrated description of the various implements and appliances used to distribute these remedies, reminding one of the illustrated catalogues of some of our large agricultural implement makers, only in these one looks in vain for any parallel to the “brushers,” “distributors,” “atomisers,” “sprinklers,”& c., that here figure. Considerations of the advantages of light and saccharine matters for attracting the moths are not lost sight of, neither is the new idea of infecting the larvae by means of the yeast fungus, although this is reported upon somewhat disparagingly. Our author, while admitting the efficacy, in greater or lesser degrees, of other insecticides, appears to fall back upon “Paris green” as the most effective, as he has done in former cases, when treating upon the Colorado beetle, &c.
The Cotton-Worm.
By Chas. V. Riley Bulletin No. 3 of the United States Entomological Commission. 8vo, pp. 1–144. (Washington: Government Printing Office, 1880.)
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The Cotton-Worm . Nature 21, 466 (1880). https://doi.org/10.1038/021466b0
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DOI: https://doi.org/10.1038/021466b0