Yes, I am well aware of the spiracular limitations of existing insect breathing and blood, but a fictitious mechanism to modify the insects can also adapt their

Yes, I am well aware of the spiracular limitations of existing insect breathing and blood, but a fictitious mechanism to modify the insects can also adapt their blood and oxygen circulation system to the larger sizes. Grasshoppers have nice hams - can you imagine herding 1000 pound gigantism adapted grasshoppers? What would you ride? Why Kangaroos - of course...;)