为日期范围和时间范围分别设置xts系列

Is it possible to subset an xts series for both date- and time-ranges in one go? E.g., in the series below I want to pick rows only for 6:30-6:50 and only for the 01-04 of a month (or better yet, the first 4 data dates of a month but that's an unrelated question). Is it possible to subset an xts series for both