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

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Identifier: usefulbirdstheir01forb (find matches)
Title: 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
Year: 1907 (1900s)
Authors: Forbush, Edward Howe, 1858-1929 Massachusetts. State Board of Agriculture
Subjects: Birds Birds
Publisher: (Boston, Mass.)
Contributing Library: The Library of Congress
Digitizing Sponsor: Sloan Foundation

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)Iedford, Mass. He made a special studv ofthe American silkworm (TdeapoJi/pliemus). Kegarding itsfood and growth he says : — It is astonishing how rapidly tlie larva grows, and one who has hadno experience in the matter could hardly believe what an amount offood is devoured h 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 larvfe is tliat thestomachs do not have tlie power of dissolving the vegetable matter received intothem, 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,Mhen i)Ut into water, expand like tea, and by the great proportion which theexcrement bears tn the (juantity of food consumed (Kirhy and Spences Ento-mology, J). 259). ^ Our Insect Enemies, by J. A. Lintner. Sixteenth Amiual Rei^ort, NewJersey State Board of Agriculture, 1888-89, p. 295.
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VALUE OF BIRDS 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 da3-s old, itweighs three grains, or sixty times the original weight; wlien thirty daysold, it weighs thirty-one grains, or six hundred and twenty times theoiiginal 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. AVhen a worm is thirty days old, it will have consumed about ninetygrains of food; but when fifty-six days old it is fully gTown, and hasconsumed not less than one hundred and twenty oak leaves, weighinothree-fourths of a pound; besides this, it has drunk not less than one-half an ounce of water. So the food taken by a single silkworm infifty-six days equals in weight eighty-six thousand times the primitiveweight of the worm. Of this, about one-fourth

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