TRICHOPTERA 



565 



Fig 



which the following brief notes are compiled. This author discusses 

 three species of Neuronia and three species of Phryganea. 



Neuronia. — The larvae are found 

 in slowly moving streams of spring 

 water; rarely they are found along 

 the edge of the large, warm streams 

 where cool seepage enters. One 

 species was found in a pond. The 

 cases are cylindrical tubes of thin, 

 rectangular bits of leaves arranged 

 in a series of rings (Fig. 695, o). In 

 the cases of old larvae the rings are 

 neatly fitted without overlapping; 

 young larvag sometimes leave the 

 hind ends of the leaf-fragments pro- 

 truding in long strips. Unlike other 

 caddice-worms, these larvje often 

 abandon their cases and wander 

 naked through the water. The form 

 of the case indicates that they are 

 not long retained ; their uniform di- 

 ameter proves that they are con- 

 structed more rapidly than the di- 

 ameter of the larva increases. When 

 the season for pupation draws near, 

 the larvas of Neuronia burrow into 

 wood, or wedge themselves beneath 



bark, or in crevices, or, if the stream bottom be of clay, they may 

 burrow into the soil. When entering the soil the larva stands on its 

 head, with its case perpendicular to the bottom, and slowly enters, 

 dragging its case with it. 



Phryganea. — The larvae live in ponds; they dwell, for the most 

 part, among submerged plants above the bottom of the pond; hence 

 they can be taken with a water net. They never abandon their 

 cases as do the larvag of Neuronia. The case is a straight tube com- 

 posed of narrow strips of leaf arranged in spiral form around the 

 circumference of the case (Fig. 695, b). Young larvae often fail to 

 cut the leaf-fragTuents used in the construction of the case into the 

 rectangular form seen in the cases of old larvas; but the bases of the 

 untrimmed fragments are arranged in a spiral (Fig. 695, c). In pre- 

 paring to pupate, the larvae leave their abode among living plants and 

 travel to some submerged log or chunk of wood and burrow into it 

 until the last bit of the case is concealed. This operation sometimes 

 requires several days of labor. When sufficient depth is reached, the 

 larva spins a silken mesh across each end of the case. 



The larva of a species of Tricenodes of the family Leptoceridas 

 makes a case somewhat similar to that of Phryganea; this is described 

 in the account of that family. 



695.— Cases of phryganeids : 

 case of Neuronia postica; b, 

 case of old larva of Phryganea 

 vestita; c, case of young larva of 

 Phryganea vestita. (After Lloyd.) 



