# import necessary libraries
import pandas as pd

# define your series
ser1 = pd.Series([1, 2, 3, 4, 5])
ser2 = pd.Series([4, 5, 6, 7, 8])

# filter using for loop
result = []
for value in ser1:
    if value not in ser2.values:
        result.append(value)

# print result
print(*result, sep = '\n')