How are the larvae and adults of S. leucitys distinguished from canicosta and albifrons? In Canada, all three species occur from Nova Scotia to Quebec, with leucitys ranging farther west to Manitoba, and canicosta on to Saskatchewan. Adult specimens of all three are shown here but there's no info in BugGuide on how to distinguish the adults or larvae of these 3 species.

I assumed that Janice could distinguish the larvae; she has reared a lot of species and is obviously experienced.
We have all 3 species in NB, the only way I can separate the adults is by genitalia dissection. Never have seen the larvae.

According to the Caterpillars of Eastern Forests site, final instars of leucitys should have only 2 white stripes on the back. The angle of view in this photo makes it difficult to see, but I can make out at least 3 white stripes on the back, suggesting either canicosta or albifrons.
I also wonder about the several adult photos IDed as White-headed Prominent on BugGuide; so far, it seems there's an assumption that every Symmerista is an albifrons - perhaps because that's the only species mentioned in Covell's guide?

Janice J. Stiefel The Symmerista leucitys female (found in Sheboygan Co. on 7/6/96) was verified from genitalia by Les Ferge, well-known moth expert in the State of Wisconsin. He either has the specimen in his collection or at the Milwaukee Public Museum. His ID surprised me, because using Covell's book, I thought it was S. albifrons. The larva photos are definitely from S. leucitys, no doubt. So far, I have three adult photos of this species (two were identified by Les). One, of course, is the one I sent to BugGuide, one is the adult that eclosed on 5/21/97 from the overwintering pupa of specimen from 7/6/96, and then I found one in Door Co. on 7/25/03. I finally found the S. albifrons, also identified by Les, in Door Co. on 7/20/03. Haven't seen either of them since.

The source & method of ID is good to know in cases like this, coupled with the knowledge that other similar-looking species of Symmerista exist, and that BugGuide currently has no info on how to distinguish among them.
I've added an explanatory statement to the leucitys Guide page, along with a request for help. Hopefully, this will encourage input, and in the meantime, caution visitors against identifying their own photos as leucitys merely because they resemble yours.

I don't accept any identification of an adult Symmerista species unless it has been verified by genitalia examination. As great a book as Covell is, I believe he has done a disservice by not mentioning that there are another 2 species of Symmerista in the East that are essentially indistinguishable from albifrons.

Janice J. Stiefel Tony, this is the same explanation I sent to Robin.
The Symmerista leucitys female (found in Sheboygan Co. on 7/6/96) was verified from genitalia by Les Ferge, well-known moth expert in the State of Wisconsin. He either has the specimen in his collection or at the Milwaukee Public Museum. His ID surprised me, because using Covell's book, I thought it was S. albifrons. The larva photos are definitely from S. leucitys, no doubt. So far, I have three adult photos of this species (two were identified by Les). One, of course, is the one I sent to BugGuide, one is the adult that eclosed on 5/21/97 from the overwintering pupa of specimen from 7/6/96, and then I found one in Door Co. on 7/25/03. I finally found the S. albifrons, also identified by Les, in Door Co. on 7/20/03. Haven't seen either of them since.

But I never did question your ID. All I did was make a species page for leucitys because the image could not be left where you put it (in albifrons). I feel I have been unwillingly dragged into the discussion (dare I say argument) between you and Robin.

Janice J. Stiefel Hi Tony! It was easier for me to send you what I wrote to Robin, just in case you needed to know. I didn't think this was an argument, it just a discussion of events and statistics. I relate what I have experienced and noted in my data base. Anyone can use it for what it's worth. I have been very careful with recording my research notes, so I speak confidently. Thanks for all your efforts. You have a remarkable website and it's very easy to use and it works pretty fast, even on our dial-up connection in the boonies.

Just a minor suggestion (not a criticism): since the whole thread is all on the same page, there's no need to copy your reply to one person in replying to another.