BX Delphini was observed in the UBV system. The V light curve shows a hump on the descending branch in the phase region 0^2 < < 0^4, although the hump in the B light curve is not so apparent. Similar humps in the V light curves are observed in Population 11 cepheids of similar period, like V527 Sagittarii and BL Herculis. The color-color diagram of BX Del lies entirely below that of the main-sequence stars, which confirms Preston's observation that BX Del is a strong-lined star with no spectral

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... peculiarity. If the hump suggested by the V light curve should be confirmed, then BX Del may be an extremely strong-lined example of Population II cepheids (just as SW Andromedae and AN Serpentis are extremely strong-lined examples of RR Lyrae stars). If, on the other hand, the hump observed is spurious, then Hoffmeister's classification of BX Del as the classical cepheid with the shortest known period is probably correct.