. Elementary lessons in zoölogy : a guide in studying animal life and structure in field and laboratory . Dragon Fly (natural size). soon as it is thoroughly stupefied by the poison, but not killed, turn it out again upon a paper, and study its re- spiratory movements. Note the regular expansion and contraction of its abdomen, and search with a lens for the minute openings of spiracles on each abdominal segment. Two larger spiracle orifices may be found on each side of the thorax. Observe the spin- dle-shaped body ; the rounded head^ con- cave behind; the wide thorax ; the- angled and tapering
. Elementary lessons in zoölogy : a guide in studying animal life and structure in field and laboratory . Dragon Fly (natural size). soon as it is thoroughly stupefied by the poison, but not killed, turn it out again upon a paper, and study its re- spiratory movements. Note the regular expansion and contraction of its abdomen, and search with a lens for the minute openings of spiracles on each abdominal segment. Two larger spiracle orifices may be found on each side of the thorax. Observe the spin- dle-shaped body ; the rounded head^ con- cave behind; the wide thorax ; the- angled and tapering abdomen. I. The Head.—Note the enormous development of the eyes. Find a minute single eye (ocellus) above the base of each antenna, and another on the median line slightly farther forward. Remove an antenna entire, and examine with a micro- scope. Compare with the antenna of a butterfly. Draw. Turn to the mouth. Find an upper, movable lip (the lahrum) and a larger, two-cleft, lower lip (the labium). Turn back the labrum and the labium, and find just beneath the labrum a pair of toothed, horny mandibles. Beneath these find another pair of jaws, also working horizontally (the maxilloe). Remove a maxilla entire, and examine it, first with a lens, and afterward with low power of the microscope. Note that it is a compound organ, made up of a two-jointed basal portion bearing two terminal append- ages. The inner appendage is the cutting or chewing part of the maxilla (the lacinia, or blade); the other append- age, standing behind or beside the lacinia, is the palpus.
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1896
