Hippodamia sinuata (Mulsant, 1850)Editthis. This species is a more prairie kind of ladybird, and can be found from Edmonton south in dry meadow and prairie habitats.
On one day late in the season I came across hundreds of these along with Parenthesis and Seven-spotted ladybirds along a scrubland habitat, the day before and the day after that there were none at all, not a single one. A way to help identify Sinuate/Convergent is if you have a Parenthesis ladybird nearby; Sinuate ladybirds are vaguely smaller and Convergent ladybirds are larger than the Parenthesis. This can be described as a smaller, fainter-marked Convergent. In some other places the Sinuate ladybird have all the spots fused into a line along the elytra; Link here; Bug Guide.