. Useful birds and their protection. Containing brief descriptions of the more common and useful species of Massachusetts, with accounts of their food habits, and a chapter on the means of attracting and protecting birds . in Medford, Mass. He made a special study ofthe American silkworm {Telea jtohjphemus). Kegarding itsfood and growth he says : — It is astonishing how rapidly the larva grows, and one who has hadno experience in the matter could hardly believe what an amount offood is devoured by these little creatures. One experiment which Imade can give some idea of it. When the young worm
. Useful birds and their protection. Containing brief descriptions of the more common and useful species of Massachusetts, with accounts of their food habits, and a chapter on the means of attracting and protecting birds . in Medford, Mass. He made a special study ofthe American silkworm {Telea jtohjphemus). Kegarding itsfood and growth he says : — It is astonishing how rapidly the larva grows, and one who has hadno experience in the matter could hardly believe what an amount offood is devoured by these little creatures. One experiment which Imade can give some idea of it. When the young worm hatches out, it ^ A probable cause for this voracity in the case of herbivorous larvae is that thestomachs do not have the power of dissolving the vegetable matter received hitothem, but merely of extracting from it a juice. This is proved both by theirexcrement, which consists of coiled-up and hardened particles of leaf, which,when put into water, expand like tea, and by the great proportion which theexcrement bears to the quantity of food consumed (Kirby and Spences Ento-mology, p. 259). - Our Insect Enemies, by J. A. Lhitner. Sixteenth Annual Report, NewJersey State Board of Agriculture, 1888-89, p. 295. .%7^t. VALUE OF BIBBS TO MAN. 31 weighs one-twentieth of a grain: when ten days old, it weighs one-halfa grain, or ten times the original weight; when twenty days old, itweighs three grains, or sixty times the original weight; when thirty daysold, it weighs thirty-one grains, or six hundred and twenty times theoriginal weight; when forty days old, it weighs ninety grains, or eight-een himdred times the original weight; and when fifty-six days old, itweighs two hundred and seven grains, or forty-one hundred and fortytimes the original weight. When a worm is thirty days old, it will have consumed about ninetygrains of food; but when fifty-six days old it is fully grown, and hasconsumed not less than one hundred and twenty oak leaves, weighingthree-fourths of a pound; besides
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbirds, bookyear1913
