Bugwarning in Yoshinogari (2006)

Hi,
I might have asked this before but I dont think I got any reply. When I went to Japan in June 2006 I went to Yoshinogari one day and up in one of the wooden towerbuildings with dolls of Japanese people from yayoi-period, etc. noticing a warningsign with a picture of a bug or something. It scared the shit out of me so I did not get any time to take a pic of it or accually reading it. This might be hard to know what it is but maybe you know or saw the same sign as me?

Was it the black widow spider? It has hour glass shaped red dots on the back.
http://www.brownreclusespider.org/black-widow-spider/black-widow-spide...
The female has poison.
It is not native to Japan but possibly came in with cargos from Australia?
They are found in Kansai region and south.
In USA I've seen them hiding in dark areas in Nevada.

Perhaps it was. Reading there might have been such insects in there really gives me the creeps. But Kansai is quite far from Northern Kyushuu, could it have gone there? I pity the person who had to go up there and put the sign up, maybe they should have put it in the entrance instead, in case of possible danger, but on the other hand they should have closed it up then.

When I recall my memory I think it could have been a centipede or caterpillar or something. I accually sent an email to the Yoshinogari staff just a few weeks past the journey but got no reply. I doubt it will lead to any answer asking them again since its more than 6 years ago.

Speaking of this, are there any poisonus insects or anything like that in Japan? I know of the huge Japanese hornet which I did not see when I was there (Maybe it does not like rain since it was rain period there). I seen some cockroaches, but they are not bad except for the way they look. Also I remember I saw a caterpillar/centipede-looking insect at the entrancefloor of WFC in Hiroshima. But I hope it was not a danger, I dont remember being bit or anything anyway.

I have not been to Yoshinogari before, but on my extensive travels across Japan, I frequently encounter warning signs about hornets:
http://en.wikipedia.org/wiki/Asian_giant_hornet

A catepillar/centipede looking thing could be a mukade... if you are brave, search for it in youtube. They are poisonous, and down south can get HUGE!

Otherwise, I don't know about in that area, but I know in some parts there is this little catepillar-type thing that hangs down on a string from trees. I can't remember if it is poisonous or not, but if you are in a naturey-type place they can be hard to avoid depending on the season! Don't remember the name either, so that may not be helpful.