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MONICA TAYLOR. 
later, were also started at Lady wood, Milngavie, the source 
of the material for all these experiments being mainly a 
rectangular iron trough near the farm-yard of Garscadden 
Mains, Bearsden. Two rafts were found during the course 
of the summer 1915 in the wooden tub, although all attempts 
in previous years to induce the imagines to lay there, or to 
lay in any of the aquaria on the premises, had failed. This 
experiment would seem to show that wild birds are not so 
easily bitten by the gnats as domestic birds, since many 
sparrows, thrushes, and blackbirds visit the small garden in 
which the tub is situated. 
The season's experience of artificial rearing showed that 
the number of egg-rafts produced under artificial conditions 
was not likely to be sufficient for a thorough investigation of 
the fertilisation processes. Moreover, unfertile egg-rafts 
were frequently obtained by Dr. Woodcook from the arti- 
ficially confined imagines, and I too obtained rafts which 
produced no larvae; while, on the other hand, egg-rafts laid in 
the open invariably produced larvae. For these reasons the 
confinement of the imagines in netted chambers was aban- 
doned, and the stocking of a pond at a convenient place in 
the country was resolved upon. 
In view of the above experiments, and of the fact that all 
the sources of material already used had been situated in the 
vicinity of farm-yards, it was decided to establish such a 
pond at Lady wood, near a stock of poultry — these latter 
birds being evidently easier of access than wild birds. 
Earlier in the summer of 1915 several small troughs, 12 in. 
in diameter, and about 6 in. in depth, had been stocked with 
larvae to serve as control experiments to those being carried 
on at Notre Dame. The results were disappointing. No 
egg-rafts appeared on these small ponds (during the summer 
of 1915). The number of female gnats seeking for hiber- 
nating quarters in the autumn of that year around Ladywood 
showed that the imagines, developed from the contents of 
the small troughs mentioned above, must have found a pond 
more suitable to the needs of their offspring than those pre- 
