Insects, etc., oi Caledonia Creek. 87 



Sub-fam. Limnophilidce. — An interesting case of this group is shown in fig. 8, 

 plate 5. It consists mainly of pieces of charcoal interspersed with sand, frag- 

 ments of stone, seeds of a raspberry, a number of the shells of Planorbis {Gy- 

 ran!"*) parvus Say, and a few valves of a species of Sphcerium. It obviously 

 belougs to a genus near to Hallesus, and may possibly pertain to the Chilostig- 

 ma coagulata, shown in fig. 2, plate 5. 



Another of the same group is given in fig. 3, plate 5. From the entirely dif- 

 ferent material of which it is constructed, as well as the manner of its construc- 

 tion, it is probably of a different species, and perhaps of a different genus, but 

 not far removed from Hallesus. It is composed principally of small pieces of 

 stone and marl, with here and there a minute shell and a hard seed. Before 

 its open end was closed with its silken grating, the larva, as an additional pro- 

 tection, had attached to it a stone, nearly covering and projecting over it at an 

 angle of 60° ; the angle is not represented in the figure. 



Fig. 9, plate 5, represents a Phryganid larval form, of which hundreds of ex- 

 amples were found in the box of Chara, much the larger number being without 

 cases, although similar in appearance to other encased ones. The vacant cases 

 observed seemed by far too few to have accommodated the large number of 

 naked forms present. Many of these latter were placed in the aquarium, but 

 nearly all were found to be dead the following day, either from injuries sustained 

 from the Mollusca, or from an unsuitable condition of the water. 



It will readily be seen that, in an aquatic form, in which the size of the abdo- 

 men is so disproportionate to the locomotive organs, some protection, like that 

 afforded by a case, is indispensable to prevent its extermination by its natural 

 enemies. Even when wholly withdrawn within its retreat, as is its condition 

 under the slightest alarm, it is not exempt from attack and destruction. Some 

 of the species of water snails as Lijuncea and others, have been seen to attach 

 themselves to the Phryganid cases, penetrate the walls, and devour the insects 

 within, wholly powerless to defend themselves against this artful approach. This 

 procedure has been observed by Dr. Hagen, who, on one occasion, in this man- 

 ner, lost nearly the entire brood of a rare species which he was rearing in an 

 aquarium in which Limncea and allied forms were present. 



When ready for their pupal change, these tubular-cased Phryganidce^&rti&Wj 

 close the opening to their dwelling by spinning across it a silken network, 

 excluding enemies, but permitting the entrance of water. The meshes are sev- 

 ered as the final transformation approaches, when the insect comes to the surface 

 of the water, and from its case, or the stem of a water-plant on which it has 

 climbed, it withdraws itself, expands its wings, and betakes itself to its new 

 element. 



VEKMES. 



Quite a number of earth worms were observed in jars to which some of the 

 mosses had been transferred. As they were not noticed at first, it is believed 

 that they were developed from ova. Their rapid increase in size was a matter 

 of no little surprise. 



A leech, brought from the stream, is at present lurking among the mosses of 

 the aquarium, having, since its first discovery, been successful in eluding recap- 

 ture. From the glimpses had of it, it is probably the common blood-sucking 

 species of the Northern States, the Macrobelella decora (Say).* 



The leeches, as a class, are not of service to the fish-culturist. Some of the 

 species have been found in the stomach of the lake white-fish (Corregonus albus 



*In a can received from Caledonia, while these pages are passing through the press (August), 

 in answer to a request for shrimps only, at least forty specimens of leeches, of two species, were 

 contained in the accompanying water plants. 



