diff --git a/mongo-ruby-driver.gemspec b/mongo-ruby-driver.gemspec
index d1bf4fa..0d4b426 100644
--- a/mongo-ruby-driver.gemspec
+++ b/mongo-ruby-driver.gemspec
@@ -43,7 +43,6 @@ PACKAGE_FILES = ['README.rdoc', 'Rakefile', 'mongo-ruby-driver.gemspec',
                  'lib/mongo/types/dbref.rb',
                  'lib/mongo/types/objectid.rb',
                  'lib/mongo/types/regexp_of_holding.rb',
-                 'lib/mongo/types/undefined.rb',
                  'lib/mongo/util/bson.rb',
                  'lib/mongo/util/byte_buffer.rb',
                  'lib/mongo/util/ordered_hash.rb',
@@ -78,8 +77,7 @@ TEST_FILES = ['test/mongo-qa/_common.rb',
               'test/test_objectid.rb',
               'test/test_ordered_hash.rb',
               'test/test_threading.rb',
-              'test/test_round_trip.rb',
-              'test/test_xgen.rb']
+              'test/test_round_trip.rb']
 
 Gem::Specification.new do |s|
   s.name = 'mongo'