"What the locust swarm has left the great locusts have eaten; what the great locusts have left the young locusts have eaten; what the young locusts have left other locusts have eaten." NIV translation
We see that this plague of locusts that has struck the land consisted of four separate bands or groups of locusts. Throughout the Bible the number four is associated with trials and this is another case of that.
"Wake up, you drunkards, and weep! Wail, all you drinkers of wine, for it has been snatched from your lips." NIV translation
The locusts destroyed the grapevines and so their will be no more wine. It seems that many times God has to allow bad things to happen to wake us up. That is what He has done with this terrible locust plague and it is what He still does today with many other types of natural disasters.
"A nation has invaded my land, powerful and without number; it has the teeth of a lion, the fangs of a lioness. It has laid waste my vines and ruined my fig trees. It has stripped off their bark and thrown it away, leaving their branches white." NIV translation
The lion is the king of the beasts and the female lion is actually bigger and more ferocious than the male. God describes the severity of this plague and the fact that the locusts have even eaten the bark off of all the fig trees. When the bark is removed from a tree, it can quickly get disease and die.
"Mourn like a virgin in sackcloth grieving for the husband of her youth." NIV translation
The people are told to mourn in sackcloth which was a rough fabric made out of goat's hair from black goats. It was used throughout the Bible as a symbol of mourning and repentance. When a young lady is engaged to be married there is the excitement of a life planned together with the man she will marry. The people are told to mourn like that young lady would when she loses her husband and those hopes and plans are ruined.