Dear WW: I have fed ants to ant lions. I think they are related to the spiders.
Here is URL to some interesting pictures of insects, but their "ant lion" is not
the one I remember:http://www.gardensafari.net/english/locusts.htm

Here's another URL about ant lions
http://www.molluscan.com/forum/htdocs/dcforum/DCForumID14/19.html

Here's URL with photo of ant lion in small sand pit:
http://www.magikcircle.com/birds/image.asp?title_id=311