In a photometric variability survey of 131 stars with B \lesssim 14 mag , we have found four new \delta Scuti stars .
We were sensitive to oscillation amplitudes as low as a few mmag .
The detection rate of short-period ( P < 0.1 d ) pulsating variable stars , which may be relevant for planned large variability surveys such as GAIA , POI , and even the LSST , was therefore 3 \% .
All four new variable stars have low pulsation amplitude ( tens of mmag ) , and one has a very short period ( 0.0198 d ) .
This star is one of the fastest known \delta Scuti pulsators .
The short period of this variable star makes it observationally tractable , and it may therefore be a particularly good candidate for asteroseismological studies .
All four new variable stars will add to the cadre of low-amplitude and relatively short-period \delta Scuti stars that are potentially useful for learning about the structure of stars on or near the main sequence , slightly more massive than the Sun .