TOILERS IN THE SEA. 



CHAPTER X. 



TUBE-MASONS. 



r I ^HOSE interesting insects, which are commonly 

 known as Caddis-flies, make for themselves, 

 when in the larval stage, minute tubes or cases, of 

 many kinds of material, agglutinated together into 

 the form of a tube ; sometimes it is chiefly of sand, 

 or small fragments of shells, and sometimes of frag- 

 ments of leaves, bark, or twigs. They are found in 

 ponds, and slow-flowing canals, and the architects are 

 larval insects of the order Trichoptera. 1 Analogous 

 to these fresh-water cases we have also builders of 

 marine cases or tubes, not the construction of insects, 

 but of annelids or worms. In the caddis-case a 

 temporary home is constructed, for a temporary pur- 

 pose, and then abandoned, but the marine masons 

 built their habitations for life, and do not usually 

 quit them till they die. Nevertheless, with all their 

 differences, there is an evident analogy between the 



1 See " Caddis-worms and their Cases," by R. McLachlan, 

 F.R.S., in Science-Gossip, July, 1868. 



