You are missing a lot of blocks there, from
http://ws.arin.net/cgi-bin/whois.pl:
ServInt Corp. SERVINT-CIDR-1 (NET-209-50-224-0-1) 209.50.224.0 - 209.50.255.255
ServInt Corp. SERVINT-CIDR-2 (NET-216-22-0-0-1) 216.22.0.0 - 216.22.63.255
ServInt Corp. SERVINT-CIDR-3 (NET-207-58-128-0-1) 207.58.128.0 - 207.58.191.255
ServInt Internet Services SERVINT-INTR-6 (NET-209-50-224-0-2) 209.50.224.0 - 209.50.224.255
ServInt Internet Services SERVINT-INTR-2 (NET-209-50-252-0-1) 209.50.252.0 - 209.50.252.255
ServInt Internet Services SERVINT-INTR-4 (NET-209-50-254-0-1) 209.50.254.0 - 209.50.254.255
ServInt Internet Services SERVINT-INTR-5 (NET-209-50-255-0-1) 209.50.255.0 - 209.50.255.255
ServInt Internet Services SERVINT-VIRH-4 (NET-209-50-233-0-1) 209.50.233.0 - 209.50.233.255
ServInt Internet Services SERVINT-INTR-1 (NET-209-50-225-0-1) 209.50.225.0 - 209.50.225.255
ServInt Internet Services SERVINT-VIRH-7 (NET-209-50-251-0-1) 209.50.251.0 - 209.50.251.255
ServInt T1 Service SRVN (NET-216-22-22-0-1) 216.22.22.0 - 216.22.22.255
ServInt T1 Service SRVN (NET-216-22-23-0-1) 216.22.23.0 - 216.22.23.255
ServInt VPS SRVN (NET-216-22-52-0-1) 216.22.52.0 - 216.22.52.255
ServInt VPS SRVN (NET-216-22-53-0-1) 216.22.53.0 - 216.22.53.255
ServInt VPS SRVN (NET-216-22-54-0-1) 216.22.54.0 - 216.22.54.255
ServInt VPS SRVN (NET-216-22-56-0-1) 216.22.56.0 - 216.22.56.255
ServInt VPS SRVN (NET-216-22-57-0-1) 216.22.57.0 - 216.22.57.255
ServInt VPS SRVN (NET-216-22-59-0-1) 216.22.59.0 - 216.22.59.255
ServInt VPS SRVN (NET-216-22-58-0-1) 216.22.58.0 - 216.22.58.255
ServInt VPS SRVN (NET-216-22-60-0-1) 216.22.60.0 - 216.22.60.255
ServInt VPS SRVN (NET-216-22-61-0-1) 216.22.61.0 - 216.22.61.255
ServInt VPS Hosting SRVN (NET-216-22-21-0-1) 216.22.21.0 - 216.22.21.255