moth id

[Kathleen Moon]

Rich and Lisa Flynn wrote:
> 
> I found a large green catapillar eating my Datura (Jimson weed).   I put it in
> an aquarium with the plant. It is now as large as my little finger,  has a
> thin diagonal black strip with one small irridescent spot on each segment.  It
> hasn't any protrusions.  This morning it has burrowed into the gravel at the
> bottom of the aquarium.  I have wedged some sticks it there.   It doesn't fit
> the pictorals in  my Audubon guide.  Any ideas?

Does it (did it) have a horn on the anal segment?  If so, it is no doubt
a sphinx moth.  Although the iridescent spot and the black strip don't
ring any bells, you can safely assume that much.  The tobacco and tomato
hornworms both have diagonal white strips (continuing on the tomato
hornworm to make a chevron around the spiracle (breathing hole).  They
are both subject to considerable variation and what you saw could well
be an extreme variation of one or the other of those two.

What I do is to put a piece of nylon screen on one end of the terrarium
for the moth to crawl onto to dry and expand its wings.  Run a thread
through the top of the screen (about a half inch down) and secure that
to the side of the terrarium with tape; this has worked well for me.  On
a few occasions, sphingids have used the top of the terrarium as well
(it is screened as well).

Good luck.

> PS I assume its a moth but don't know for sure.