Matthew Poole and continuators on Revelation 9:10

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

A kind of Venemous Serpents

that have their Stings in their Tails, with which they presently kill both Men and Beasts.

What these five months mean, is very hard to say, certainly it is a certain number for an uncertain, and mentioned rather than any other times, because it is (as they say) the usual time of the life of Locusts; though some observe, that five months have in them (counting as the Hebrews, 30 days to the month) 150 days, and a day standing for a year, as in Prophetical Writings, it denoteth the just time the Saracens raged in Italy, from the year 830, to the year 980; as to which I refer my Reader to search Histories.