Green Alder Sawfly (Monsoma pulveratum)

I rarely report details on insect sightings, but doing so just in case it's of any benefit to anyone studying the habits of this sawfly, and the implications of its presence It looked familiar to me and I wonder if I had not seen it before, but that could simply be some familiarly with another insect... just don't know.

The sawfly was sitting atop a leaf just under the flower buds on the stalk of Fragrant Fringecup (Tellima grandiflora) flowers, perhaps 10-15" off the ground. Although I attempted to avoid disturbing it in order to get pictures of the plant and the insect, I was a bit surprised, but not overly so, on getting a few shots without it taking flight (I did not attempt to probe it to determine its alertness, and was not aware of the invasive status of this particular insect at that time. With a reported lifespan or a week more or less, I suppose it was just finishing it's emergence, or quite possibly had finished mating (if male), or egg laying (if female).

I read of alarm in 2010 with this showing up in Washington state. To date, and not including the possible addition of this sighting, BugGuide's "Data" still shows WA as the only lower 48 state to be confirmed by BugGuide. In WA, previously there were 10 hits in Washington in April (all adults, but possibly representing as few as 2-3 actual individuals), 0 in May, 0 in June, and 1 in July (larva). All adult sightings were early April.

Where: Near Cougar Mountain "Million Dollar View" site off parking lot near end of SE Cougar Mountain Drive. Plant/insect found south of viewpoint covered decking, perhaps by 50 feet, in open area.
When: Sun, 5/7/17 11:50AM
Elevation: 1,430'
Weather: Mostly sunny. Nearby personal weather station reported 50-51 degrees between 1130-1200pm. (Plant/insect were in exposed sunlight)

Comments Subsequently Added:
-- While not on Red Alder at the time, the local habitat included alder, likely rather nearby.
-- Looking closely, I'm wondering if it might have expired at this point (I was running late, forgot to or just chose to skip an overhead shot, which I would normally capture)
-- Although first seen in WA in 2010, few new adults posted, last appears to be 2013
-- Other BugGuide sightings of species adults were early April. This sighting, a month later, might be partially explained by:
.......... Higher elevation... this being over 1400 feet
.......... Unusual winter / spring weather, including: (1) Prolonged cool/cold periods (early May day was first day over 70-deg in 219 days)
.......... Unusual winter / spring weather, including: (2) Monthly and winter season precipitation records set
-- No adults in WA posted on BugGuide since 2013, but this may be misrepresentative of activity level of this invasive species