. Insect life; an introduction to nature study and a guide for teachers, students and others interested in out-of-door life. Entomology; Nature study. POND LIFE. 133. be found to bear at its hinder-end a rosette of five platelike lobes ; this is shown at a in Fig. 109. This rosette can be seen imperfectly with a good lens. When a larva reaches the surface it spreads out the r6sette upon the surface film, which buoys it up in the same way that we have seen a needle supported by this film (see experiment i, pagre 104). The body fiq- 109.—«, end of , . , . , ,. , , , . breathing-tube of of the la
. Insect life; an introduction to nature study and a guide for teachers, students and others interested in out-of-door life. Entomology; Nature study. POND LIFE. 133. be found to bear at its hinder-end a rosette of five platelike lobes ; this is shown at a in Fig. 109. This rosette can be seen imperfectly with a good lens. When a larva reaches the surface it spreads out the r6sette upon the surface film, which buoys it up in the same way that we have seen a needle supported by this film (see experiment i, pagre 104). The body fiq- 109.—«, end of , . , . , ,. , , , . breathing-tube of of the larva is only slightly heavier larva; *, breath- than the water, and the buoyant effect ™^ " ^° ''"^^" of the surface film on the rosette is sufficient to over- come this difference. 5. Consider the adaptations in structure to the mode of life of this insect: The form of the respira- tory tube enables it to rest at the surface of the water, where it can get a supply of air, while the greater weight of the fore end of the body causes it to hang down into the water in a position suited to collect- ing the minute particles of decaying vegetation scat- tered through the water and upon which the insect feeds. This position is also one that enables the in- sect to start quickly on its wriggling journey when alarmed. 6. If the student has the use of a microscope, it will be well for him to make at this point a larger and more detailed figure of a larva than that given above, which was introduced merely to show the general form of these insects in this stage. The Pup^ of Mosquitoes [School JVork).—The larvae of mosquitoes develop rapidly, and after a few molts change into club-shaped pupee, the head and thorax being greatly enlarged in this stage. The. 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 wo
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