October 1S91.] 



PSYCHE. 



155 



Sericostomatidae. I have found 

 six species of Sericostomatidae, of 

 which the most interesting belong to 

 Helicopsyche. Species of this genus 

 make small, snail-like cases of sand, 

 gravel or mud. The one whose 

 case is figured (fig. S) uses coarse *■© 

 sand. I find it crawling on stones |S) 

 or weeds where the current is Fig-, s. 

 rapid. In pupation the mouth of this 

 snail case is closed with an operculum in 

 which is a small eccentric slit. At the 

 apex of the spiral, which represents the 

 back door of the larva, tnere is a lacunose 

 disk. These larvae were found pupat- 

 ing on June 2nd. 



A species of Brachycentrus is some- 

 times common and sometimes 

 scarce. It makes a quadrangular fl 

 case (fig. 9) of a few square bits s 

 of bark, fastened together at their Flg ' 9 ' 

 edges. 



Once I found a number of empty 

 ~. cases (fig. 10) made of sand; 

 l! they were small, club-shaped, 

 and curved, and probably the 

 lg ' I0 " makers belong in this family. 

 One of the most abundant species in 

 Stony Brook (and in other brooks 

 where I have collected) belongs "near 

 Mormonia or Trichostoma." 

 The case (fig. n) is arched on 

 the back, and fiat or slightly 

 concave below, and is made of 

 gravel, with small stones on each 

 side, and is about 12 mm. long. I have 

 found similar cases in Jamaica Pond. 

 During pupation the cases are closed at 

 each end with a small stone, but to in- 

 sure a current of water through the case, 



Fig. 11. 



each of these little stones is attached to 

 the case by a row of short threads, look- 

 ing not unlike the teeth of a moss 

 capsule. Fig. 12 shows their /J§|p 

 appearance at the ventral side 

 of the head end, where is the '"' ' 

 point of attachment. 



Even more abundant than this species 

 is one which makes cylindrical, slightly 

 curved tubes of sand, (fig. 13), 

 which, when their inhabitants are 

 pupating, often are found attach- 

 ed to each other in large masses. 

 At this time each end of the case Fig. 13. 

 is closed with a grain of gravel, and I 

 cannot see what provision is made for 

 the respiratory current. The larva, how- 

 ever, has a small hole at the side of the 

 sand grain which serves to close the pos- 

 terior end of his case. The case of the 

 growing larva flares somewhat at the an- 

 terior end, but that of the adult is evenly 

 cylindrical. I have an imago of this 

 species which I reared from the egg, in 

 the tranquil waters of my aquarium, but 

 when the pupae are taken from the 

 brook, they should be kept in running 

 water to transform. On April 17th, 

 1S90, I found multitudes of these cases 

 in Stony Brook near the Mount Hope 

 station. I supposed that the larvae had 

 pupated, since both ends wei'e closed, 

 but keeping out of water for a few min- 

 utes one of the stones to which they 

 were attached, most of the little larvae 

 opened their front doors, and stretched 

 far out to see what had become of the 

 brook. By another month, however, 

 they really had changed to pupae. 

 Some of the imagos of this species, 



