There's a 2010 thread
[webmasterworld.com] on this.
Unable to locate anything newer.
22.214.171.124 - - [17/Oct/2012:21:29:56 +0100] "GET /MyFolder/MySub/MyPage.html HTTP/1.1" 403 559 "http://www.google.com/search" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.4 (KHTML, like Gecko; Google Web Preview) Chrome/22.0.1229 Safari/537.4"
Within two seconds there were five requests for different pages (followed by a standard users IP duplicating initial page request).
Three from the 74.125. range and two from this 173.94 range.
Anybody seeing this new range?