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"

-----Original Message-----
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
Marylyn Pillsbury
So Hero