290 SALMON AND TROUT. 
matter whence their name of ‘ faggot insects’ is derived. The 
maggot-like larve form for themselves cases for shelter or 
security in which they dwell for many months before they quit 
the water and take the air as flies. They carry their wings 
when crawling—which they do much more freely than the 
Lphemere—not raised in pairs above the thorax, but folded 
pent-house fashion above the abdomen. The larvz are com- 
monly known as ‘caddis’ or case worms, and the abodes they 
construct for themselves, partly by the use of their strong 
nippers and partly by the aid of some natural glue furnished 
by their own bodies, exhibit a curious and interesting variety. 
These ‘cases’ ascend by a graduated scale from the simplest 
to the most complicated forms. First we have an inch of 
slender rush ; then a more solid tenement formed from a piece 
of stick, in which the grub takes the place of the pith; then 
two leaves’ gummed together at the edges. Anon we finda 
fasciculus of tiny twigs, or a small clustered pillar of rush-rods, 
cut accurately to one length: and curiously joined together. 
The most beautiful of all are cylindrical grottos, sometimes 
nearly two inches in length, formed of small fresh-water shells. 
A studious entomologist who was also a fly fisher might do 
worse than to make a collection of these ingenious dwellings 
and figure the ‘imago ’ hatched from each. It would, I presume, 
be found that each class of dwelling belongs to a different 
species. I have found many kinds together in one spring 
ditch or sedgy backwater, so that there must have been a choice 
of material, though I cannot affirm that when I have dislodged 
the inmates for bait I have noticed any marked differences but 
those of size and colour. 
It would be a curious experiment to transport a large 
number, say of the rush worms, to a stream where they would 
find no rushes, and then to observe whether, after the flies had 
hatched and bred, their progeny would disappear or would 
protect themselves by adopting some new building material. 
But I am digressing. Let me return to my fly book, and 
say that the artificial flies representing the Phryganee have 
