catch species not found errors in search

app/models/item.rb

@@ -321,12 +321,20 @@ class Item < ActiveRecord::Base
   end
   
   search_filter :only do |species_name|
+    begin
       id = Species.require_by_name(species_name).id
+    rescue Species::NotFound => e
+      raise SearchError, e.message
+    end
     arel_table[:species_support_ids].eq(id.to_s)
   end
   
   search_filter :species do |species_name|
+    begin
       id = Species.require_by_name(species_name).id
+    rescue Species::NotFound => e
+      raise SearchError, e.message
+    end
     ids = arel_table[:species_support_ids]
     ids.eq('').or(ids.matches_any([
       id,

app/models/species.rb

@@ -3,7 +3,9 @@ class Species < PetAttribute
   
   def self.require_by_name(name)
     species = Species.find_by_name(name)
-    raise ArgumentError, "Species \"#{name.humanize}\" does not exist" unless species
+    raise NotFound, "Species \"#{name.humanize}\" does not exist" unless species
     species
   end
+  
+  class NotFound < ArgumentError;end
 end