. Elementary lessons in zoölogy : a guide in studying animal life and structure in field and laboratory. Zoology. 46 INSECTS. have essentially the same structure, — a double fold of membrane supported by chitinous veins, — and they are very similar in development. Study of the Nymph. — Place a large nymph in a small dish with just enough water to cover it, and study it alive, with the aid of a good lens. Observe : — 1. Its sturdy/orm. 2. Its large eyes. 3. Its short antennoe. 4. Its enormous loiver Up., covering the lower and front parts of the head. Seize the edge of it with fine-pointed forc
. Elementary lessons in zoölogy : a guide in studying animal life and structure in field and laboratory. Zoology. 46 INSECTS. have essentially the same structure, — a double fold of membrane supported by chitinous veins, — and they are very similar in development. Study of the Nymph. — Place a large nymph in a small dish with just enough water to cover it, and study it alive, with the aid of a good lens. Observe : — 1. Its sturdy/orm. 2. Its large eyes. 3. Its short antennoe. 4. Its enormous loiver Up., covering the lower and front parts of the head. Seize the edge of it with fine-pointed forceps, and pull it forward for exami- nation. Note that it is so jointed to the head that it can be extended far forward, and quickly retracted. Note that it is two-lobed, that the lobes are triangular, tfiat each bears an incurved hook at the apex, that each is toothed along its inner margin, and that the A Dragon-fly Nymph, whole is a very formidable grasping organ. 5. Its mouthy with well-developed mandibles and max- illse inside the labium. 6. Its rudimentary wings. Compare with those of the adult. 7. Its well-developed legs. Compare them in position with the legs of the adult. 8. The regular expansion and contraction of its abdo men in respiration. Note the striking unlikeness of the respiratory methods in the adult and in the nymph. The adult lives exclusively in the air ; the nymph, exclu- sively in the water. Both must get oxygen from the air. Internal branching and intercommunicating air tubes, which open exteriorly at the spiracles in the adult, con-. 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 Needham, James G. (James George), 1868-1956. New York : American Book Company
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1896
