They are indeed Sphinx moths (Family Sphingidae).
The 3 species that occur in the Eastern US are:
Hemaris thysbe - Hummingbird Clearwing Brown scaled areas of wing; Brown scaling uneven on inside edges
Larval food includes hawthorne, honeysuckle, various Prunus sp., snowberry.
Hemaris diffinis - Snowberry Clearwing Black scaled areas of wing; body usually more yellow than red/brown
Larval food includes dogbane, honeysuckle, snowberry.
Hemaris gracilis - Slender Clearwing Brown scaled areas of wing; Brown scaling smoother on inside edges
Rarest of the three. Larval food is primarily Early low blueberry.
References indicate they are around all summer, though I expect at our latitudes, more so in late summer.
Mike Blust, Professor of Biology
101 Ames Hall
Green Mountain College
Poultney, VT 05764
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" Good things come to those who wade"
From: Marylyn Pillsbury [mailto:[log in to unmask]]
Sent: Sunday, August 03, 2003 12:21 PM
To: [log in to unmask]
Subject: Re: hummingbird moths
I looked them up on the internet under Sphinx moths .From what I actually
saw, I believe they were large Clearwing Moths which are a category of
Hummingbird moths which are Sphinx moths. Correct me if I am wrong