INTERESTING STONE HOUSES. 



While the children were playing in a 

 small brook, they found something en- 

 tirely new to them, and as usual, came 

 with hands full, shouting, "We have found 

 something new ! Do you know what 

 these are?" 



These new treasures proved to be the 

 larvae of the caddis fly in their stone 

 houses. This little creature is noted for 

 its complete metamorphosis. The female 

 fly often descends to the depth of a foot 

 or more in water to deposit her eggs. As 

 the eggs hatch the habits of their larvae 

 are exceedingly interesting. 



They are aquatic, being long, softish 

 grubs, with six feet. The fish are very 

 fond of them, for which reason they are 

 in great demand for bait. The angler 

 looks for "cad-bait" along the edges of 

 streams, under stones, or on the stalks of 

 aquatic plants. One can easily see that 

 their lives are not free from care and dan- 

 ger, and so to protect themselves, they 

 are very wise in building cylindrical 

 cases in which they live during this dan- 

 gerous period. The different species, of 

 which there are many, seem to have their 

 individual preference as to the substance 

 which they employ in building these 

 houses, some using bits of wood, others 

 shells, pebbles, or straws. They readily 

 disregard these preferences when there is 

 a lack of the material which they usually 

 prefer. 



Those brought to me were made of 

 different colored pebbles and were very 

 pretty homes. We counted the pebbles 

 in one of them and found there were 

 eighty-nine used, and built so securely 

 that it could not be easily crushed by our 

 ringers. They were all about an inch in 

 length, a quarter of an inch in diameter 

 and were perfect cylinders with a large 

 pebble fastening one end ; so no fish could 

 catch them unawares. We placed them in 

 water, where we could watch their devel- 

 opment. They never willingly left their 



homes, only thrusting the head and a por- 

 tion of the body out in search of food. 



When about to pass into the torpid 

 pupa state, they fastened their houses to 

 some sticks and stones in the water, and 

 then closed the end with a strong silken 

 grating, which allowed the water to pass 

 freely through their houses, keeping them 

 sweet and fresh. We are told that this 

 fresh water is necessary for the respira- 

 tion of the pupa. Thus they remain quiet 

 for a time until they are ready to assume 

 the imago form. When that important 

 period arrives they make an opening in 

 the silken grating with a pair of hooked 

 jaws, which seem to have developed while 

 resting in the pupa state. They also have 

 become efficient swimmers, using their 

 long hind legs to assist them. After en- 

 joying this new exercise of swimming for 

 a short time they evidently become 

 anxious for a wider experience, and com- 

 ing to the surface of the water, usually 

 climbing up some plant, the skin of the 

 swimmer gapes open and out flies the per- 

 fect insect. Sometimes this final change 

 takes place on the surface of the water, 

 when they use their deserted skin as a 

 sort of raft, from which to rise into the 

 air, and away they go to new fields and 

 new experiences. These insects are 

 known as the caddis-fly of the order 

 Neuroptera, having four wings, measur- 

 ing about an inch when full spread, with 

 branched nervures, of which the anterior 

 pair are clothed with hairs ; the posterior 

 pair are folded in repose. The head is 

 furnished with a pair of large eyes, with 

 three ocelli, and the antennae are gener- 

 ally very long. 



If you know the haunts of this interest- 

 ing house builder, scatter some bright 

 sand and tiny pebbles in the water, and 

 when they are deserted, gather the houses 

 for your collection. 



Rest H. Metcalf. 



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