28 
CORN AND GRASS. 
time unknown a drinking-place had been made for cattle by forming 
a pool across the course of the pipes, taking up a portion of them, so 
that the water ran into the pool on one side pure and clean, and 
replacing them on the other, so that the water-supply went on again 
from the pool, in whatever state the water might have become there. 
The pool was noted as full of duckweed and green slime, and was open 
to defilement by cattle standing in it; and on inspection the Sanitary 
Officer stated that the water was injurious to the health of those 
drinking it. A list was sent to me of various water-insects which had 
floated down the pipe, and which came with the drinking-water on 
turning the tap. These included Dragon-fly grubs, also grubs of 
some of the large water-beetles, and other insects besides those I 
had seen. 
The above observation is of service in turning attention to the need 
of looking, when unaccountable illness occurs, as to what may have 
happened where supply-pipes are open, even to possibility of being 
tampered with, and likewise to note that, though Marsh Daddy Long- 
legs grubs and others may do no harm beyond being exceedingly dis¬ 
gusting when appearing from a tea-kettle, yet that the foul mud that 
suits them, and the dirty weedy water that suits other larvae, are sure 
parents of illness, and the presence of the grubs is a sure sign of 
something amiss that should be looked to without loss of time.* 
Corn Thrips. Thrips cerealium, Haliday; T. physapus, Kirby. 
The attack of Corn Thrips is one of those which often does a great 
deal of harm very quietly, and without the cause of the mischief being 
suspected, on account of the minute size of the insect, which is 
scarcely more than the sixteenth of an inch long. 
Thrips are well known to gardeners as being troublesome in frames, 
and they are also generally well known as the little black speck-like 
insects often seen wriggling actively about in flowers; often, too, by 
* The larva differed from those of the common crop Tipulce in being decidedly 
larger, likewise in having a tuberculated caudal proleg; this was formed of two long 
and pointed tubercles, each placed on a gibbous or tuberculated base. The speci¬ 
mens sent were of various ages, and the only description I find corresponding with 
them is that of Reaumur, vol. iv.,p. 194, in which he says:—“ The figure represents 
an aquatic larva of one of the kinds that produce Tipulide flies. It differs from 
the ground larvae of Tipulides in the fact of the sort of horns, the round and fleshy 
appendages attached to the caudal extremity being longer than those of other 
Tipulide larvae.” The description is accompanied by a figure fairly representing the 
long fleshy filaments placed in a bunch beneath the caudal extremity; but I failed 
to procure specimens of the perfect Daddy Longlegs to which it would in course of 
time develop. 
