308 The Caddis-Worm and its Houses. 



selves in their houses, and thus resist the attacks of any 

 enemy who may endeavour to pull them forcibly out of their 

 abodes. 



These cases or houses, which the caddis so tenaciously 

 guards, are made of different materials, depending upon 

 the locality in which it lives, and also the kind of sub- 

 stances it is able to procure. For instance, if the caddis 

 inhabits still waters, such as ponds where water plants abound, 

 or gently running streams, it will often use the leaves of those 

 plants, and with them most ingeniously make for itself most 

 comfortable and beautiful houses. The leaves are in this case 

 arranged in such a manner that it would seem that not only 

 comfort but also beauty of structure is considered. It is quite 

 a curious sight to see these creatures walking about at the 

 bottom of the water encased in these green portable houses, to 

 which are usually attached a piece of stick or a stone to pre- 

 vent the caddises and their dwellings from rising to the surface. 

 Sometimes half a dozen may be seen at one time, and in each 

 there is a slight difference of construction, according to the 

 taste and convenience of the worms. It should be perhaps 

 here added, that after the house is completed the head and legs 

 of the larva are the only part which is visible, the rest of the 

 body being always kept encased in its domicile. But these 

 green houses are not the only kinds which are found in still 

 waters. Other kinds may be seen which are made of very small 

 stones, almost as fine as sand, and there are others again 

 which are made up entirely of sticks, their length and size 

 varying much. 



In rapid streams, as cases made from leaves of water plants, 

 and stones, so small as those just mentioned, would be speedily 

 swept away by the current, we find that they are built of 

 more solid and heavier kinds of materials. In such streams, 

 if made of stones, the caddis cases are much larger and 

 heavier. 



One of the most curious of all tho different kinds of houses 

 or cases are (hose which arc entirely made of shells of creatines 

 inhabiting the same stream as the caddis-worms. These cases 

 are frequently found bo be constructed of shells of tho Plan orbis, 

 a small snail, arranged in a most grotesque manner. Frequently 

 the creatures are alive in these shells employed by tho caddis 

 in making its house, and then when it walks about it carries 

 the shelled animal, very inncli lo the discomfort of tho latter. 



Such aro the most frequent kind of caddis cases which aro 

 found in bhe rivers and ponds of Great Britain. But it by no 

 means follows that the caddises aro incapable of making them 

 from other kinds of materials than those found in tho water 



