Elementary studies in insect life Elementary studies in insect life elementarystudie00hunt Year: 1902 FIG. 116. Different stages in transformation of parasitic fly (Sarcophaga sp.): J, 2, 3, 4, white maggot in active stage ; 5, maggot beginning to pupate—dirty white in color, pupa-case light brown; C, 7, fully developed pupa-case of two species. X 5. house-fly. These flies are parasitic upon grasshoppers, and aid in keeping the grasshoppers in check. Some of these flies are illustrated in Figures 117 and 171. In regard to pollination of crops, reference has already been made to the fact that
Elementary studies in insect life Elementary studies in insect life elementarystudie00hunt Year: 1902 FIG. 116. Different stages in transformation of parasitic fly (Sarcophaga sp.): J, 2, 3, 4, white maggot in active stage ; 5, maggot beginning to pupate—dirty white in color, pupa-case light brown; C, 7, fully developed pupa-case of two species. X 5. house-fly. These flies are parasitic upon grasshoppers, and aid in keeping the grasshoppers in check. Some of these flies are illustrated in Figures 117 and 171. In regard to pollination of crops, reference has already been made to the fact that the honey-bee materially in- creases the yield of the alfalfa plant. (See page 107.) It is known that the bumblebee is very influential in bringing about the proper fertilization of the common red-clover blossom. However, injurious insects, such as the grasshopper, may not be looked upon as wholly in- jurious, since they frequently furnish food for the farmer's poultry. High-class farm culture tends to re- duce the numbers of injurious forms, and at the same
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