Miss E. M. Smee on the Caddis-worm. 401 



feet, turning it on all sides to discover whether it will fit into the 

 space, and if it does not, as is frequently the case, that piece of stone 

 is instantly rejected, and another is tried after the same manner, until 

 they succeed in finding a suitable piece, when it is cemented to the other 

 stones by a secretion which I ascertained proceeded from their mouth. 



" When their house is made, the body of the creature is completely 

 encased ; their heads and feet alone protruded, 



" In their natural state, the weight of these cases varies much. 

 They are twice as heavy, and made of more solid materials, when the 

 creatures inhabit rapid streams than when they live in still waters. 

 The reason of this difference is, I suppose, to enable themselves to 

 keep, by the weight of their cases, at the bottom of the water. 



" I noticed that, after the Caddis-worms were turned out of their 

 cases, air-bubbles appeared on the surface of their bodies. If placed 

 under these circumstances in running water, these air-bubbles would 

 cause the creatures to rise to the surface and there float until they 

 died from exhaustion, caused by their hard endeavours to reach the 

 bottom. According to the roughness of the water, so must be the 

 weight of their cases. 



" When in the pupa-state, their heads and feet are entirely with- 

 drawn into their cases ; and they remain in a dormant state, neither 

 eating nor moving, until they turn into flies, their cases being more 

 or less split in the act of transformation. 



" I used to feed some of my Caddises whilst in the larva state with 

 small pieces of raw meat, which they ravenously devoured; they would 

 even eat a common house-fly, leaving only the wings, head, and legs ; 

 but however hungry they might be, yet they never could be induced 

 to touch cooked meat. 



" I found it was qmte necessary for the Caddises to have plenty of 

 food whilst in the larva state, to enable them to have strength to un- 

 dergo the transformation. 



" Trout are the great enemies of the Caddises, as they eat them up, 

 cases and all, in every stage of their existence ; but they consider the 

 worms without the cases as especially dainty morsels. 



" On the 24th of January this year, I observed that the Caddises 

 were just hatched ; and although some were so small that they were 

 only visible with a lens, yet every one was busily employed in making 

 its little house. 



" They have grown so quickly that, since that date, they are now 

 quite conspicuous at the bottom of the river. 



" The box I send to you contains in the centre the cases made 

 from the various materials I gave to the worms, and encircling the 

 artificial cases are the natural habitations as taken from the river. 



" Trusting you will find them worthy of your inspection, 

 " Believe me to remain, 

 " My dear Sir, 

 " To Br. Gray, F.R.S., " Yours faithfully, 



of the British Museum." "Elizabeth Mary Smee." 



" P.S. The Caddises are so excessively pugnacious that I am 



