The incident was missed by the officials, who were following play some distance away, so the culprit escaped uncarded, whereas Ireland had had loosehead prop Maura Coulter harshly sinbinned for infringing a quarter of an hour into the second period.
Scotland, who had taken the lead with a penalty from scrumhalf Paula Chalmers, sister of Craig, in stoppage time at the end of a first half, a half in which the Irish too often found themselves on the wrong end of the Welsh referee's whistle, clinically capitalized on their temporary numerical advantage.
Just as in the men's game and in their own previous match against England, Ireland's lineout was a shambles and it was from a stolen throw that the Scots spread right and worked winger Jen Dickson over in the corner with an hour on the clock.
A penalty was awarded following the Boyd incident, but impressive young fullback Sarahjane Belton drew a blank to go with a miss just before the break from Ulster skipper Rachel Reid, both attempts being from considerable range. The kick could have brought Ireland back to within a single score of the visitors but, in the event, the home side were to cruelly concede a second try in the 11th minute of a staggering 16 added on in the second half.
With Coulter having been carried off shortly after her return from the sinbin and her replacement Magali Dolo going off injured a few minutes later, Ireland brought Ulster loose forward Eryka Wessell on in the front row. She has occasionally filled in as an emergency prop in the English Premiership but hurt her neck in the first scrum here and then, in the second, Ireland were driven off their own ball five metres out and Scottish
It was ill-reward for the gallant greens, for whom flanker Fiona Steed, being watched for the first time in an international by her boyfriend, Ireland prop John Hayes, was in inspired form with an awesome display of tireless tackling and covering, rescuing her team on more than one occasion.
Although coach Donal O'Leary and his team are fed up being the bridesmaids, this was another encouraging outing for Ireland and it was particularly pleasing to see younger players like Boyd, Belton, Patrique Kelly and Maeve Quirke really holding their own at this level in support of the incomparable Steed.
Following two near misses at their new Thomond Park home against Wales and Scotland, Ireland now host Spain at the same venue on March 23.
IRELAND: SJ Belton; S Fleming (capt), P Kelly, R Boyd, L Cantwell (R Howell, 66 mins); N Milne, K Eagleson; M Coulter (M Dolo, 75; E Wessell, 86), E Collins (J Lonergan 66), E Coen, M Quirke, A-M McAllister, R Reid (R Foley, 66), M O'Loughlin, F Steed.
SCOTLAND: S Higgins; J Dickson, R Petlevannaia, R Shepherd, A Hutt; D Fairbairn, P Chalmers; K Findlay (capt), A McKenzie, A Christie, L O'Keefe, J Hanley, C Muir, D Kennedy, F Gillanders.