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Sawyer - Monochamus scutellatus - female

Sawyer - Monochamus scutellatus - Female
Mt. Washington, Coos County, New Hampshire, USA
July 2, 2007
Size: about 19 mm
I think this is Monocha*mus marmor*ator despite its difference in color and markings from others of that species already on bugguide. I was stripping bark from a dead conifer in the middle krummholz forest zone on Mt. Washington in my Forest Service-approved search for Py*tho str*ictus, finding a few Py*tho larvae. Suddenly, out of a round hole in the trunk, this good-sized longhorn came clambering up to greet me. I'm afraid I don't know what the tree species was.

Although most of the associated images are of this specimen after it died, this image and the next one are of the living beetle.

Images of this individual: tag all
Sawyer - Monochamus scutellatus - female Sawyer - Monochamus scutellatus - female Sawyer - Monochamus scutellatus - female Sawyer - Monochamus scutellatus - female Sawyer - Monochamus scutellatus - female Sawyer - Monochamus scutellatus - female Sawyer - Monochamus scutellatus - female Sawyer - Monochamus scutellatus - female Sawyer - Monochamus scutellatus - female Sawyer - Monochamus scutellatus - female Sawyer - Monochamus scutellatus - female USDA wants to know - Monochamus scutellatus - female USDA wants to know - Monochamus scutellatus - female USDA wants to know - Monochamus scutellatus - female USDA wants to know - Monochamus scutellatus - female

Moved from Monochamus.

Monochamus scutellatus, confirmed
After examining this specimen carefully, I conclude that it is Monochamus scutellatus. Even though the coloration of the pubescence is more yellow-golden rather than white, it is still consistent with variation in the species. Many specimens in the Cornell collection also have a yellow coloration to the pubescence. All other characters match that of M. scutellatus. Besides M. sutor (which was mentioned by someone as a possibility), I also considered M. galloprovincialis which looks somewhat similar to M. scutellatus as well. All of these Monochamus have the apices of the elytra rounded or truncate and without any acute apical spines. However, other characters of these two Palearctic species do not match that of the specimen you provided.

Department of Entomology
Comstock Hall
Cornell University
Ithaca, New York

Uncertain after physical comparisons
I made a trip with this specimen to the New Hampshire state entomologist's office today to show the beetle to John Weaver there. We agreed that this beetle had no semblance of points, acute angles, or spines of any sort on the elytral apices and morphologically resembles M. scutell*atus more than any other indigenous species (he had series of each). We are both hesitant to assign it to that species, however, due to the dull golden color of the pubescent patches on the elytra, pronotum, and scutellum.

Monochamus scutellatus and sutor
My first opinion is that your specimen was M. scutellatus.
This is the more probably thing since you collected it in US.
But, if you see some differences, you must check if your specimen might be another (also introduced) species.

The main difference between M. scutellatus and M. sutur is that the body of the former shows metallic reflections, while the latter is completely opaque.
Your first pictures had clear reflections, the second two, not.
Secondly, M. scutellatus is marked with white pubescence, M. sutur with yellow one.
This beetle seems to me yellow.

Nevertheless, a picture may mislead.
You has this specimen and you can personally check it.

Doug Yanega,
in private correspondence, tenders his first impression of this photographed specimen as M. scutel*latus and his opinion remains the same after viewing Web images and a physical specimen of M. sut*or.

Moved from Longhorned Beetles.


Monochamus caroliniensis or scutellatus
It should be rather a female of Monochamus carolinensis (Olivier, 1792) or M. scutellatus scutellatus (Say, 1824), well distinguishable through its different elytral pattern.
You can confront the types at:

The elytral apex is teratologic, maybe due to an insufficient environmental humidity; therefore, the elytral spines (diagnostic character) are not well distinguishable.
Moreover, I can't understand if the insect is brown or the pictures have a yellow light dominance...

Thank you, Francesco.
I would rule out scut*ellatus because the scutellum and elytral markings are a dull gold rather than the usual brilliant white.

I noticed the deformity but doubt there was insufficient humidity since the beetle came charging out of its hole in solid wood of a small dead tree that had normal moisture below the bark I was stripping.

I viewed the images on the CDFA site you linked to and have added it to the Monochamus Info page. While I agree that it is a female based on its "short" antennae and is therefore likely to be more parallel-sided (males are tapered from humeri to apices), I am still not able to decide on carolin*ensis.

I will shoot the (now) dried specimen in more detail this morning, including elytral apex and some shots in natural lighting.

Monochamus choice
(Un)fortunately the choice for a north-eastern Monochamus is not wide.
There are only: scutellatus, notatus, marmorator, caroliniensis and titillator.
M. notatus, marmorator, and titillator have a dark-light pattern, while your specimen has only the light pattern.
The other two species seem simple: scutellatus is black with white marking, caroliniensis brown with yellowish marking.
Moreover, scuellatus has mutic elytral apex and caroliniensis spined elytral apex.
If you still have got this specimen, you can check the difference.

I don't see a spined elytral apex
in the detail images I'm uploading now. That puts me (us?) back to genus.

Could Say, Leconte and friends have missed a Monochamus species that might restrict itself to the Krummholz zone?

foreign Monochamus
Dear Jim, by using Breuning's key to world-wide Monochamus I can reach only 3 species like that: M. scutellatus, M. impluviatus from Western Siberia and Korea and M. sutor sutor from Europe.
I have all these species in my collections and, after having confronted your specimen, I came to the conclusion that yours is a female of Monochamus sutur, or (less possibly) a new still-not-described species.

Would you like to examine the specimen?
I only keep specimens in case they are needed for identification or desired by others. I would like to find out whether it is invasive or undescribed. (If the latter, it would be the second undescribed species I have found, the other being a euc*nemid.)

Anyway, email me a shipping address and it's yours for examination. Let me know if I should soften it and send it in alcohol or send it dried. I have an idea Don Chandler at UNH would like the specimen eventually if that is okay with you.

M. scutellatus
To me it looks like scutellatus. I would say definitely not carolinensis. True, the spots are yellow rather than white but the dark bronze elytra, boldly spotted scutellum, and no spines lead me to this.
I don't know how much can be made with the yellow rather than white and the shape is a bit elongate for a female. Another possibility to consider is a hybrid, possibly scutellatus x marmorator. Quote from The Forest Insect Survey of Maine, Order Coleoptera, Insect Disease Division Technical Report No. 32, Dec., 1993 by Dearborn and Donahue:
Most (Monochamus) are very distinctive and easily identified. However there is good evidence that natural interbreeding between species does occur and that hybrids are occasionally collected. Good series of forced hybrids and back crosses (F1 and F2) are available for study in the insect collection of the Entomology Department at the University of Maine in Orono.
I think the reference they list for this is Fickus, T. P. 1956. The sawyer beetles in Maine. Orono. Me. Agric. Exp. Sta. Maine Farm Research. 3:14-21, but I haven't seen that paper or the actual collection in Orono.
Still, we'll keep hope that you've discovered a new white mountain endemic as that would be very cool.

Very interesting.
I think I'll see if I can get an opinion from Dearborn on these images.

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