The Holy Bible, Revelation 16:10-11

10 And the fifth angel poured out his vial upon the seat of the beast; and his kingdom was full of darkness; and they gnawed their tongues for pain,

11 And blasphemed the God of heaven because of their pains and their sores, and repented not of their deeds.

The Holy Bible, Revelation 9:1-12

1 And the fifth angel sounded, and I saw a star fall from heaven unto the earth: and to him was given the key of the bottomless pit.

2 And he opened the bottomless pit; and there arose a smoke out of the pit, as the smoke of a great furnace; and the sun and the air were darkened by reason of the smoke of the pit.

3 And there came out of the smoke locusts upon the earth: and unto them was given power, as the scorpions of the earth have power.

4 And it was commanded them that they should not hurt the grass of the earth, neither any green thing, neither any tree; but only those men which have not the seal of God in their foreheads.

5 And to them it was given that they should not kill them, but that they should be tormented five months: and their torment was as the torment of a scorpion, when he striketh a man.

6 And in those days shall men seek death, and shall not find it; and shall desire to die, and death shall flee from them.

7 And the shapes of the locusts were like unto horses prepared unto battle; and on their heads were as it were crowns like gold, and their faces were as the faces of men.

8 And they had hair as the hair of women, and their teeth were as the teeth of lions.

9 And they had breastplates, as it were breastplates of iron; and the sound of their wings was as the sound of chariots of many horses running to battle.

10 And they had tails like unto scorpions, and there were stings in their tails: and their power was to hurt men five months.

11 And they had a king over them, which is the angel of the bottomless pit, whose name in the Hebrew tongue is Abaddon, but in the Greek tongue hath his name Apollyon.

12 One woe is past; and, behold, there come two woes more hereafter.

Journal of Discourses, Orson Pratt 16:43

[I]f we read the revelations of St. John, we find that when the fifth angel shall sound his trump, the bottomless pit shall be opened, and there shall come forth a great smoke, and a cloud of locusts, so great that the sun and air shall be darkened; and these locusts shall have power to torment men five months before the sounding or the sixth trump. This shows that there will be a period of at least five months, between the sounding of the trumps of the fifth and sixth angels.