Forest Katydid: Unknown Caribbean Orthopteran with Cyan-colored Eyes is Nesonotus tricornis

Subject:  Blue eyed grasshopper
Geographic location of the bug:  Saint Lucia, Lesser Antilles
Date: 04/19/2021
Time: 08:02 AM EDT
Your letter to the bugman:  No photo shop!!    This grasshopper, found in the open bathroom of our guest house here in Saint Lucia,  has electric blue eyes.     Date, April 19.     Local man says it is a “Clap-Clap” from call at night.   Is it known?   An earlier post had photo of this insect as “unknown orthopteran”.
How you want your letter signed:  Madeleine

Dear Madeleine,
We cannot believe that 13 years have passed since that 2008 posting of the Unknown Caribbean Orthopteran with blue eyes, and there is a noticeable dearth of images online that illustrate this amazing insect.  It is also quite interesting that you also took images of this same unidentified Orthopteran in Saint Lucia, so there must be a population of them on the island.  First we would like to make a few corrections.  This is not a Grasshopper.  Grasshoppers are Orthopterans, but they have short antennae.  The members of the order with long antennae belong to the suborder Ensifera which includes Katydids and Crickets.  Also, we originally referred to this eye color as blue, but in teaching the color wheel to our photo and cinema students, we draw a distinction between the colors blue and cyan, and the eye color of this critter is definitely cyan.  See Reddit or Quora for the difference between blue and cyan.  That said, we are still not able to provide a species identification for this awesome insect.  We will attempt to contact Piotr Naskrecki who is an expert in Katydids to see if he recognizes it.

Thank you very much!    Since I wrote you, I found Nesonotus tricornis on the internet.   It seems to be a perfect match.     What do you think?   Yes, Katydid of course, and yes, Cyan.    A local man here in St Lucia saw my picture (I have others, by the way) and said it was a “clack-clack” for the noise it makes at night.    We have been hearing a katydid or two sing (or clack, it is kind of mechanical) at night.    Quite low pitched.
We loved this insect!    He was calm, drank some water, walked on us, didn’t fly….though I suppose eventually it did.
Madeleine Love (usually in Maine)

Update:  Thank you so much for getting back to us Madeleine, and based on images posted to Nature Picture Library (where Piotr Naskrecki provided the image) and iNaturalist, we agree that this is likely Nesonotus tricornis.  According to the Dutch Caribbean Species Register, the common name is Forest Katydid.