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Photo#823387
Macrosiagon sp.? - Macrosiagon octomaculata - female

Macrosiagon sp.? - Macrosiagon octomaculata - Female
Santa Cruz River, Amado-Montosa Road, Santa Cruz County, Arizona, USA
July 26, 2013
Size: ~1cm
Found on seepwillow. When editing the image I noticed what appear to be eggs in the leaf below (hers?).

Images of this individual: tag all
Macrosiagon sp.? - Macrosiagon octomaculata - female Macrosiagon sp.? - Macrosiagon octomaculata - female

Macrosiagon octomaculata --det. Z.H. Falin
his comment: "I would have to check the literature, but oviposition records are fairly rare for Macrosiagon. I would not expect her to lay her eggs on a curled up leaf!"

Moved from Macrosiagon.

 
Eggs & Det
Regarding the likelihood of Macrosiagon ovipositing on leaves, Zack can have a friendly debate with the author of this reference :-)

I would expect Macrosiagon to lay eggs on flowers, rather than leaves, so the tiny triungulins wouldn't have to travel far looking for a host wasp to carry them to their quarry. But I often do see wasps taking a rest on leaves...although, admittedly, that would seem a statistically less promising place than a flower from which to hitch a ride for the triungulins.

Regarding the det of M. octomaculata rather than M. pectinata...I guess I got derailed at the key break:

    "Vertex rounded, front surface convex".....M. pectinatum

                vs.

    "Vertex truncate, front surface flat or slightly concave"....leading to M. octomaculatum.

The former seemed the better choice to me...though neither Alice's images nor mine give a clear anterior or posterior view of the vertex for clearly ascertaining those characters.

Rivnay's description of M. octomaculatum gives another character for females of that species...namely, "processes of female antennae bifurcate". I gather that's a more subtle character to "see" than one might initially think, from Rivnay's figures here of antenna with bifurcate processes (Fig. 14a) vs. simple processes (Fig. 13a). In the bifurcate processes, one branch appears to lie parallel to and flat against the main axis of the antenna...making it especially hard to discern. Nevertheless, I think I may see bifurcate processes on the right antenna in my full-size image of the same individual in Alice's photo above.

Alice, pretty sure our gal here is...
...M. pectinata. See remarks under my post below:



Hopefully Zack Falin will be able to confirm or correct.

Neat you noticed the eggs. I think her ovipositor looks somewhat like it has the equivalent of a "milk moustache" in both our photos.

PS: I think your nice Flickr posts from Hereford may also be M. pectinata...but, unlike here, a form with the female having black pronotum. Apparently color can be variable in Macrosiagon...especially in the M. pectinata which is so variable it's thought to be a species complex.

Moved
Moved from ID Request.

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