Horntail - Tremex columba

Pigeon Horntail

Keyed out using a key to the Siricidae and Ibalidae of the Eastern United States by Smith & Schiff. Based on the following characteristics (shown in this and the following images):

- Hind tibia with one apical spur (1)
- antenna with 15 segments
- Hind wing with anal cell (2)
- Body without long golden hairs

… Stephen Luk, 25 April, 2007 - 9:21pm

Moved

Moved from Horntails.

… Stephen Luk, 25 April, 2007 - 9:17pm

Sirex Woodwasp

Looks like a Sirex Woodwasp (Sirex noctilio). The have the enlarged hind legs, smoky wings and no abdominal markings.

… Michael Garcia, 20 September, 2006 - 9:16am

Schiff et al. (2006)

Thanks for looking and offering your opinion. However, I'd still go with T. columba given the 15-segmented antenna, which keys out in couplet (1) in Schiff et al. (2006), "Guide to the Siricid Woodwasps of North America". A mostly unmarked, smoky-winged male is illustrated.

… Stephen Luk, 7 January, 2011 - 8:42am

Urocerus?

Might be in the genus Urocerus. There is some way to tell the difference, I think by the shape and length of the first hind tarsal segment, which is clearly visible in this image.

… Eric R. Eaton, 19 September, 2006 - 6:07pm

I think a Tremex male

Based on overall habitus and above all shortness of the antennae (both Sirex and Urocerus having distinctly longer ones). This could even be simply a T. columba (common Pigeon Horntail) male, as a striking color sexual dimorphism is the rule in this group.

… Richard Vernier, 24 September, 2006 - 6:40am

A horntail on a stump really stumps me

... excuse the pun :-) Yes, the tarsal segment does indeed point to a Urocerus ... though the lack of yellow patterning is still confusing me.

… Stephen Luk, 19 September, 2006 - 6:45pm

Urocerus

I agree with Stephen Luk that this is a pigeon horntail. Urocerus has two apical spurs on the hind tibia. Concerning the antennal segments, according to "Guide to the Siricid Woodwasps of North America" put together by the FHTET (http://www.srs.fs.usda.gov/pubs/ja/ja_schiff004.pdf) the only siricid with less than 16 antennal segments is Tremex.

… Kevin Chase, 7 January, 2011 - 6:51am