--- a/mobile/android/base/java/org/mozilla/gecko/BrowserApp.java
+++ b/mobile/android/base/java/org/mozilla/gecko/BrowserApp.java
@@ -1723,18 +1723,16 @@ public class BrowserApp extends GeckoApp
                 overridePendingTransition(0, 0);
             }
 
         } else if ("Telemetry:Gather".equals(event)) {
             final BrowserDB db = getProfile().getDB();
             final ContentResolver cr = getContentResolver();
             Telemetry.addToHistogram("PLACES_PAGES_COUNT", db.getCount(cr, "history"));
             Telemetry.addToHistogram("FENNEC_BOOKMARKS_COUNT", db.getCount(cr, "bookmarks"));
-            Telemetry.addToHistogram("FENNEC_FAVICONS_COUNT", db.getCount(cr, "favicons"));
-            Telemetry.addToHistogram("FENNEC_THUMBNAILS_COUNT", db.getCount(cr, "thumbnails"));
             Telemetry.addToHistogram("FENNEC_READING_LIST_COUNT", db.getReadingListAccessor().getCount(cr));
             Telemetry.addToHistogram("BROWSER_IS_USER_DEFAULT", (isDefaultBrowser(Intent.ACTION_VIEW) ? 1 : 0));
             Telemetry.addToHistogram("FENNEC_TABQUEUE_ENABLED", (TabQueueHelper.isTabQueueEnabled(BrowserApp.this) ? 1 : 0));
             Telemetry.addToHistogram("FENNEC_CUSTOM_HOMEPAGE", (TextUtils.isEmpty(getHomepage()) ? 0 : 1));
 
             if (Versions.feature16Plus) {
                 Telemetry.addToHistogram("BROWSER_IS_ASSIST_DEFAULT", (isDefaultBrowser(Intent.ACTION_ASSIST) ? 1 : 0));
             }

--- a/mobile/android/base/java/org/mozilla/gecko/db/LocalURLMetadata.java
+++ b/mobile/android/base/java/org/mozilla/gecko/db/LocalURLMetadata.java
@@ -176,18 +176,16 @@ public class LocalURLMetadata implements
                 } else {
                     urlsToQuery.add(url);
                 }
             } else {
                 urlsToQuery.add(url);
             }
         }
 
-        Telemetry.addToHistogram("FENNEC_TILES_CACHE_HIT", data.size());
-
         // If everything was in the cache, we're done!
         if (urlsToQuery.size() == 0) {
             return Collections.unmodifiableMap(data);
         }
 
         final String selection = DBUtils.computeSQLInClause(urlsToQuery.size(), URLMetadataTable.URL_COLUMN);
         List<String> columns = requestedColumns;
         // We need the url to build our final HashMap, so we force it to be included in the query.

--- a/toolkit/components/telemetry/Histograms.json
+++ b/toolkit/components/telemetry/Histograms.json
@@ -3392,32 +3392,16 @@
     "low": 0,
     "high": "8000",
     "n_buckets": 20,
     "releaseChannelCollection": "opt-out",
     "description": "Number of bookmarks stored in the browser DB",
     "alert_emails": ["mobile-frontend@mozilla.com"],
     "bug_numbers": [1244704]
   },
-  "FENNEC_FAVICONS_COUNT": {
-    "expires_in_version": "40",
-    "kind": "exponential",
-    "high": "2000",
-    "n_buckets": 10,
-    "cpp_guard": "ANDROID",
-    "description": "Number of favicons stored in the browser DB *** No longer needed (bug 1156565). Delete histogram and accumulation code! ***"
-  },
-  "FENNEC_THUMBNAILS_COUNT": {
-    "expires_in_version": "40",
-    "kind": "exponential",
-    "high": "2000",
-    "n_buckets": 10,
-    "cpp_guard": "ANDROID",
-    "description": "Number of thumbnails stored in the browser DB *** No longer needed (bug 1156565). Delete histogram and accumulation code! ***"
-  },
   "FENNEC_READING_LIST_COUNT": {
     "expires_in_version": "50",
     "kind": "exponential",
     "high": "1000",
     "n_buckets": 10,
     "cpp_guard": "ANDROID",
     "description": "Number of reading list items stored in the browser DB *** No longer needed (bug 1156565). Delete histogram and accumulation code! ***"
   },
@@ -8154,23 +8138,16 @@
     "n_values": 30,
     "description": "Algorithms used with WebCrypto (see table in WebCryptoTask.cpp)"
   },
   "MASTER_PASSWORD_ENABLED": {
     "expires_in_version": "never",
     "kind": "flag",
     "description": "If a master-password is enabled for this profile"
   },
-  "FENNEC_TILES_CACHE_HIT": {
-    "expires_in_version": "40",
-    "kind": "linear",
-    "high": "13",
-    "n_buckets": 12,
-    "description": "Cache hits on the tile-info metadata database *** No longer needed (bug 1156565). Delete histogram and accumulation code! ***"
-  },
   "DISPLAY_SCALING_OSX" : {
     "expires_in_version": "never",
     "kind": "linear",
     "high": "500",
     "n_buckets": "100",
     "description": "Scaling percentage for the display where the first window is opened (OS X only)",
     "cpp_guard": "XP_MACOSX"
   },