EXPERIMENTAL SITE 
The experimental site was located at the Central Experiment 
Station, Cocoa Board, and the Eastern Caribbean Farm Institute for 
the following reasons: The bat problem had been apparent for a 
number of years; the houses are uniformly constructed to a standard 
plan; the occupants, who are scientists, appreciated the problem and 
were willing to cooperate; and the necessary equipment, materials 
and labor were readily at hand. 
EXPERIMENTAL LAYOUT AND TYPES OF HOUSES 
For the main experiment the houses were distributed as shown 
on the plan (Figure 4) and consisted of eleven two-storied, L-shaped 
buildings, each of approximately 1,410 square feet roof space within 
walls and covered with corrugated asbestos-cement sheets (Figure 3). 
The floors of the roof spaces, which are also the ceilings of the 
rooms below, consisted of pressboard fixed together by thin wooden strips. 
A set of wooden louvres was situated at each end of the L and at the 
right angle of the L,. There was also a trap door at each end of the 
L, or in some cases there was only one situated at the end of the long- 
est side. One house was selected as a control, which remained untreated 
throughout the trial period. Other houses were selected for experimen- 
tation at a later date and these are described separately. 
Obviously, the total number of experimental houses (in the same 
location and of similar construction) is too small to permit valid 
statistical projection, 
MATERIALS AND METHODS OF APPLICATION 
It was decided to use the four generally available chlorinated 
hydrocarbon insecticides, B.H.C., D.D.T., chlordane, and dieldrin, in 
various formulations, at different concentrations and applied in several 
ways: by smoke generators, hand-operated high-volume pneumatic sprayers, 
power-driven high-volume sprayers, low volume power driven sprayers or 
mist blowers, and power-driven dusters. Miscellaneous equipment used 
included aluminum expansion and step ladders, rubber torchlights, vacuum 
cleaner, brushes and dust pans for removing bat guano, asbestos plates 
for safe support of the smoke generators, polythene bags for transport- 
ing dead bats to the laboratory, measuring bucket and scales for pre- 
paring spray mixture, protective clothing and face masks for spraying 
purposes, counting aids for recording bat populations, thermohydrograph, 
etc. 
