Need to start each threads with delay [on hold]

I have multiple threads ruing. I want them to start with delay timer of 5 seconds. For ex: Thread1 starts with t seconds, Thread2 starts with t+5 seconds, Tread3 starts with t+10 seconds and so on. How can I do this, by changing the code below ...

from threading import Thread  
import time 

def Device(i):
     print "Thread%d starts in %d" %(i, time.time())
     # Thread1 needs to start with t seconds
     # Thread2 needs to start with t+5 seconds
     # Thread3 needs to start with t+10 seconds
     .......

for i in range(100):
     t = Thread(target=Device, args=(i,))
     t.start()

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