. Lessons in nature study. Nature study. BKOOK INSECTS 65. Fig. as. A Caddice-fl}-. flies (fig. 38), moth-like flying insects, with four wings covered with hairs, among which are distributed many flattened scale- like hairs. The autennje are very long and thread-like and the in- sects may be found fluttering among the foliage or alight upon it, at the brook's margin. Collect and put into the school- room aquarium a number of those caddis worms (in their cases) which you find in the quiet places of the brook. These may live in the aquarium and an opportunity thus had to observe their habits mor
. Lessons in nature study. Nature study. BKOOK INSECTS 65. Fig. as. A Caddice-fl}-. flies (fig. 38), moth-like flying insects, with four wings covered with hairs, among which are distributed many flattened scale- like hairs. The autennje are very long and thread-like and the in- sects may be found fluttering among the foliage or alight upon it, at the brook's margin. Collect and put into the school- room aquarium a number of those caddis worms (in their cases) which you find in the quiet places of the brook. These may live in the aquarium and an opportunity thus had to observe their habits more closely and also, perhaps, to observe the manner of their transformation into winged adults. The caddis worm or young caddis-fly^ does not transform directly into the winged form as does the youijg stone-fly or May-fly. When ready to transform it closes the opening of the case by spinning a silken sheet across it or filling it with a stone, The opening is not absolutely closed, but space is left for the ingress of water which carries oxygen to the insect within. Thus , the caddis worm changes to a pupa, that is, to a stage in which the insect lies quiescent, taking no food, while it is underg9ing the great structural changes neces- sary for the development of the caddis-fly from the caddis worm. The occurrence of this change to a pupa (pupation, the changing is called) can be recognized by noticing the closed-up condition of the case. Such closed cases may be found in the brook, and perhaps in the aquarium. Open one of these closed cases and examine the pupal caddis-fly within. Note how the legs and the developing wings of the caddis-fly are folded against the body. Can you find any tracheal gills on the pupa? Can the pupa move? It can only wriggle a little. This wriggling or bending of the body is necessary to keep going some sort of a current of. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readabili
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