Mustard Whites (or Veined Whites) hindwing veins can range from light to heavy gray/brown scaling. They are found in woodlands and forest edges, in cool, moist places. Their host plants include crucifers which include mustards, cabbages, broccoli, turnips, cresses. This photo is from summer in northern Minnesota.
Here are a few of the Lepidoptera insects in my backyard.
Here is a Variegated Fritillary I saw on a recent walk.
Here is a White-Lined Sphinx Moth visiting my Dianthus flower plant last night.