78 



RANDOM NOTES ON NATURAL HISTORY. 



Phryganea. 



The old English word Cadas means a 

 case for security. The word still lingers in 

 tea-caddy. The case-worm or larva of 

 Phryganea is a soft-bodied creature, but it 

 has a firm head and strong jaws. It is sup- 

 plied with six legs, well adapted for loco- 

 motion, and with two hooks at the end of 

 the tail by which it secures itself in its 

 case. It is a rapacious and pugnacious in- 

 sect. It feeds upon fresh-water mollusks, 

 larvae, polyps, etc. As a builder it makes 

 use of the materials at hand. The old 

 Free Masons may have taken a lesson from 

 it, and Longfellow might have had it in 

 mind when he sang, — 



"That is best which lleth nearest, 

 Shape from that thy worlv of art." 



Sometimes the case is made of sticks, 

 sometimes of grains of sand, and, in Great 

 Britain, sometimes of the shells of the 

 small river-snail (Planorbis), even while 

 their proper owners have them in occupa- 

 tion. The cases not only serve for protec- 

 tion but for anchorage also, and the}^ are 

 found to be the heaviest where the current 

 is strongest — the creature having added 

 materials to increase the weight. 



If the caddis be deprived of his case, it 

 will at once set to work to construct 

 another ; and, in confinement, it will build 

 of materials supplied to it, such as small 

 fragments of glass and coral and the broken 

 teeth of combs. However rough the out- 

 side of the case may be, the inside is per- 

 fectly smooth, for it is lined with the same 

 cement which binds the materials together, 

 and which is exuded from the mouth of the 

 creature. 



It is interesting to watch the caddis shift- 

 ing his ground, moving his habitation from 

 one part of the river-bed to another. So 

 much of the body as will allow the legs free 

 motion is protruded, and the creature 

 strains like a horse with a heavy load, 

 whilst its dwelling moves forward more or 

 less steadily accordingly- as it presents a 

 smooth or roughened surface. 



Before the pupa change takes place the 

 caddis draws itself entirely into its snug 

 quarters, and spins a strong netted cover- 

 ing over the entrance to the case. Having 

 thus " barred the door " against intrusion, 



it dozes oflf into the long sleep, the waking 

 from which shall be an introduction to a 

 new life, in another element. 



The Phryganid;e in their perfect state dif- 

 fer from others of the Neuroptera, in that 

 they are covered with minute hairs. 

 Hence Westwood and other English natural- 

 ists have classed them as a separate order, 

 the Trichoptera (Gr, Bin'^, hair ; -re/x-v, a 

 wing) or hair\'-winged insects. 



In dress the Phryganidfe are a sober peo- 

 ple — browns, drabs and yellows are their 

 favorite colors. Cross-venations give 

 their wings a netted appearance. Their 

 antennaj are long — in some instances very 

 long, and the wings are carried longitudi- 

 nally. The females deposit their egg- 

 masses early in August on some surface 

 projecting from the flood. Woodward tells 

 us {Int. to Mod. Class, of Lis., Vol. II., 

 page 62) that occasionally they descend 

 the stems of water-plants and lay them un- 

 der water. The egg-mass resembles minia- 

 ture frog-spawn. It is an accumulation of 

 drops of gluten containing embr^'ons in the 

 form of minute green specks. The young 

 larvfe burst forth in September, and pro- 

 ceed at once to construct their dwelling. 

 Thej- afterwards repeatedly " lengthen 

 their cords and strengthen their stakes" 

 according to their requirements. 



" Our rivers abound with _fish of various 

 kinds, which at particular seasons derive a 

 principal part of their food from insects, 

 as the numerous species of the salmon and 

 carp genus. These chiefly prey upon the 

 various kinds of Trichoptera in their larva 

 state called case or caddis-worms, and in 

 their imago, May-flies." {Kirby and 

 Spence, Int. to Ent., Letter IX.) 



The adult salmon proper, Salmo salar, 

 is believed by the best authorities, to eat 

 little or nothing during its sojourn in fresh 

 water. It leaves the ocean fat and returns to 

 it emaciated. The above remark, therefore, 

 does not apply to Salmo salar ; but it does 

 apply to others of the genus, and especially 

 to the English Sahno fario. or common 

 trout ; and the Canadian Salmo fontinalis, 

 the brook trout ; and Salmo 7iaymacush, 

 the lunge. The lake shad (Coregorivs al- 

 biis) , also is well known to have a keen 

 relish for the Phryganidae in their winged 

 state. — Report of Ontario Entomological 

 Society. 



