Riding Fail

When i try to summon a item riding a silverfish (there are to many details to list) it will fail and say unbalanced curly brackets, this is my command:

/summon Item ~ ~1 ~ {Item:{id:367,Count:1,tag:{}},PickupDelay:32767,Age:-32768},Riding:{id:Silverfish {CustomName:"Rotten Flesh",CustomNameVisible:1,CanPickUpLoot:0b,Attributes:[{Name:"generic.maxHealth",Base:1},{Name:"generic.followRange",Base:500},{Name:"generic.knockbackResistance",Base:1f},{Name:"generic.movementSpeed",Base:0.5f},{Name:"generic.attackDamage",Base:1}],Silent:1,DropChances:[2F,0F,0F,0F,0F],Equipment:[{id:"minecraft:rotten_flesh",Count:1},{},{},{},{}],ActiveEffects:[{Id:14,Amplifier:0,Duration:2147483647}]}}}

What I expected to happen was...:
It would summon my mob

What actually happened was...:
It said Unbalanced curly brackets {}

Steps to Reproduce:
1. Enter the command above into a command block
2. Power the command block