Edit your .htaccess rule to block traffic from these unwanted bot visitors –
# block visitors referred from semalt.com
RewriteEngine on
RewriteCond %{HTTP_REFERER} semalt\.com [NC]
RewriteRule .* – [F]
# End semalt block
# block referer spam buttons for website
RewriteEngine On
RewriteCond %{HTTP_REFERER} buttons\-for\-website\.com
RewriteRule ^.* – [F,L]
# End buttons for website block
http://www.street-punk-productions.com/block-semalt-buttons-website-bots/