Mercury has his kiore-henua as number 59 (counted from Ca1-1), a number which presumably indicates the dark night at the end of 2 months, and henua is here depicted in a shape similar to that of henua for Venus (in her kiore-henua glyph):

Mercury
Ca3-5 Ca3-6 Ca3-7 Ca3-8 (59)
Venus
Ca3-14 Ca3-15 Ca3-16

Venus has aquired a little peg up front in her henua, whereas Mercury has lost a similar part from his.

Mercury comes after Mars. While Mars brings light (hau tea), Mercury brings land (henua), of a sort:

 
Ca3-3 Ca3-6

3 * 3 = 9 and 3 * 6 = 18. The season of dry land (henua) will come after light has been brought by Mars into the sky. Mercury is located between spring and autumn, in high summer.

But Mercury must also carry out his important function to fertilize the dry earth by bringing down heavenly rain:

Mercury
Ca3-5 Ca3-6 Ca3-7 Ca3-8 (59)

Quicksilver (the 'living', quick, silver) runs downwards.

Mercury, Jupiter, and Venus, are necessary agents in bringing forth:

Ca3-2 Ca3-3 Ca3-4
Ca3-5 Ca3-6 Ca3-7 Ca3-8 (59)
Ca3-9 Ca3-10 Ca3-11 Ca3-12 Ca3-13
Ca3-14 Ca3-15 Ca3-16
Ca3-17 Ca3-18 Ca3-19 Ca3-20

Mars and Saturn form the beginning and end of the process.

Two 'halves' are evident, up to and including Mercury respectively from Venus. The primary 'half' stretches up to midsummer, ending in the 'deluge'. The second 'half' is coming at the end of autumn, beyond the centrally positioned Jupiter.