Yes, I think those are the spider mines. I found all three types of trap material (scorpions, spider eggs, and... whatever the other one is), but just sold them. When you select the Deadly Gift skill as your secondary skill, a menu will appear to choose which type of trap to use, depending on what type of trap material you have in your inventory.
If you have not had him arrested yet, Tingalf in Ars Magicana is one of the best sources of survivor supplies, including traps. If you have an updated version of the game (1.0034A as shown in the bottom right corner of the main menu) or installed the patch before starting the game, then Finnigan in the cellar of the Ducal inn in Verdistis also carries survivor supplies.
IIRC Blake in Ars Magicana and Mpenzak in Verdistis seemed to have trap material a little more often than other random merchants, though not as much as Tingalf or Finnigan.
If you quick save before running your mouse over an item/chest/merchant or hitting the alt key, you can identify the item or trade with the merchant, then quick load to get different stats or inventory. This can be done repeatedly to get the best stats or specific bonuses on an item (save after finding good candidates) or looking for specific items (such as spellbooks or charms) from merchants. Don't waste too much time with this, though, it really isn't necessary to get the best possible equipment.
.. i don't even know what they are 
..the bouncing things that go boin boing boing i guess ?? 
