. Injurious insects : how to recognize and control them . Insect pests; Insect pests. PREDACEOrS A.\D PARASITIC INSECTS 1 1 the dragon fly, poised in air and waiting to pounce on some unwary gnat or fly, is predaceous. A parasitic insect, on tlie other hand, usually is liigljy specialized for existence on some particular species of host, and has reached such depend- ence on its host that if the latter dies before the parasite has completed Fig. 4S- â Larva, showing exit holes of parasites. Fig. 49. -Eggs of a parasite on a cut- worm. Original. its life round, the parasite perishes.
. Injurious insects : how to recognize and control them . Insect pests; Insect pests. PREDACEOrS A.\D PARASITIC INSECTS 1 1 the dragon fly, poised in air and waiting to pounce on some unwary gnat or fly, is predaceous. A parasitic insect, on tlie other hand, usually is liigljy specialized for existence on some particular species of host, and has reached such depend- ence on its host that if the latter dies before the parasite has completed Fig. 4S- â Larva, showing exit holes of parasites. Fig. 49. -Eggs of a parasite on a cut- worm. Original. its life round, the parasite perishes. JNIany parasitic insects live within the liodies of their hosts. A familiar example is found in the species that lays its eggs in the body of the tomato worm, the parasitic grubs finally gnawing their way to the surface, where they spin tiny, white cocoons on the body of their host. For most of us, the tremendous work of para- sitic and predaceous spe- cies in destro^â ing insect pests passes unnoticed. It is brought to mind when we see or hear of a bad outbreak of some injurious insect, and later observe that the threaten- ing species has suddenly grown scarceâeometimes seemingly disap- peared from the face of the earth in the very localities where it had been abundant. If we were to follow up such cases carefully, we should find, as a rule, that as soon as the threatening species. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original O'Kane, Walter Collins, b. 1877. New York : The Macmillan Company
Size: 2595px × 963px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectinsectp, bookyear1912
