for reference Josephine's marriage record in 1906 gives her parents as William Killilea and Mary Hughes, and reported age as 22 so born about 1884 - I see births of at least two children in the extracted civil birth collection - Martin 1872 and Margaret 1869 (this collection does not include all births and only only covers up to abt 1882)
Baptism transcripts on RootsIreland shows several further children :
Bridget (1) 1875
Winifred (1) 1877
Bridget (2) 1883
Winifred (2) 1886
all baptised Annaghdown Catholic parish - Delia can be a nickname for Bridget... maybe your Josephine Delea/Delia was baptised as Bridget but took on the name Josephine in later life ?
Bridget (1) and Winifred (1) probably died young, and the names were used again...
Here's the civil birth entry for Bridget born 22nd July 1883, Grange townland Turloughmore civil sub-district, Galway registration distrct to parents William Killilea and Mary Hughes, residence is also Grange townland, father is a labourer.
p.s. this Grange townland is in Annaghdown civil parish, and it looks like two of.children, Martin and Winifred, still lived in the same place at the time of the 1901 census.