156 WATERCRESSES. 
The figure (p. 153) is given just to show the general appearance of 
the perfect insects of this small order of Trichoptera, and is one of 
the genus Mormonia; but for general practical purposes, the Caddis 
Worms and Caddis Flies are too well known, and especially to fishers, 
to need description. 
In reply to the notes sent me on January 22nd regarding the loss 
being suffered by a Watercress grower in Hampshire from what 
proved on examination to be Caddis Worms, I suggested that a greater 
amount of fish in the water would probably reduce the amount of the 
Caddises, and received the following note, showing the destructive 
powers of the grubs, and likewise that in this case the increase of birds 
which specially fed on the fishes which had previously held the water 
grubs in check, was at the root of the mischief :— 
* January 27th.—I have just returned from a visit to the man's 
Watercress beds. Three-quarters of the area of them have been 
eaten, and the poor fellow is in trouble as to how he will be able to 
meet his rent of £20 for the half an acre. He tells me that as soon 
as certain flies appear these insects disappear. I have advised him to 
get some trout; his reply was, ‘there were plenty of trout till the 
herons came.’ ”’ 
As for local reasons it appeared that the presence of the herons 
was irremediable, and the grower's lease terminated in the course of 
the year, nothing further was requisite in this instance; but the 
following notes, which were kindly sent me, on April 80th, by Mr. 
Richard Coe, of Weston Farm, Albury, Guildford, give some very 
useful information as to treatment for getting rid of Caddis-attack, or 
keeping it in check. 
PREVENTION AND Remepirs (from Mr. Richard Coe).—‘‘ The pest 
you name, commonly called ‘Cads’ in this locality, gives us much 
trouble every season, though sometimes more than others. This year 
there is rather less than more of the nuisance. 
‘Shrimps * are also very numerous, but with quick-lime can be 
effectually dealt with ; not so the Caddis Worm. Whenever we find 
a bed of Cresses attacked, we clear away all the plants, drain off the 
water, and leave the bed perfectly dry for two or three weeks in the 
autumn, previous to the winter planting. If afterwards we find traces 
of the worm, we wait until the plants are well established, then we 
increase the volume of water, and swim the bed, and pass the backs 
of wooden rakes over the tops of the plants very thoroughly. This 
process brings the buik of the worms to the surface, and they are let 
off down stream with the surplus water. 
* Specimens of these were not sent me, so I cannot say which of the small 
freshwater existences they might be. 
