'In contrast' vs. 'by contrast'

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“In contrast” vs. “by contrast”

 “In contrast” and “by contrast” mean the same thing: the act of comparing in order to show differences. The difference lies in the way the words are used. “In contrast” is usually followed by “to” or “with” and requires a noun to follow it. “By contrast” is usually followed or preceded by the subject of the sentence.

Examples:
In contrast to the diligent bee, the butterfly flies hither and yon with no apparent purpose.
In contrast with the chorus of birdsongs in my backyard, my front yard is serenaded by the sound of rumbling buses flying down the street.
By contrast, the Picasso is more vibrant and full of life.
The cats will often sleep the day away. The dogs, by contrast, never settle down.