between the towns Illiturgi and Mentissa.  The entrance of this defile Nero seized, and Hasdrubal, to prevent his being shut up in it, sent a herald to engage that, if he were allowed to depart thence, he would convey the whole of his army out of Spain.  The Roman general having received this proposition gladly, Hasdrubal requested the next day for a conference, when the Romans might draw up conditions relative to the surrender of the citadels of the towns, and the appointment of a day on which the garrisons might be withdrawn, and the Carthaginians might remove every thing belonging to them without imposition.  Having obtained his point in this respect, Hasdrubal gave orders that as soon as it was dark, and during the whole of the night afterwards, the heaviest part of his force should get out of the defile by whatever way they could.  The strictest care was taken that many should not go out that night, that the very fewness of their numbers might both be more adapted to elude the notice of the enemy from their silence, and to an escape through confined and rugged paths.  Next day they met for the conference; but that day having been spent, on purpose, in speaking and writing about a variety of subjects, which were not to this point, the conference was put off to the next day.  The addition of the following night gave him time to send still more out; nor was the business concluded the next day.  Thus several days were spent in openly discussing conditions, and as many nights in privately sending the Carthaginian troops out of their camp; and after the greater part of the army had been sent out, he did not even keep to those terms which he had himself proposed; and his sincerity decreasing with his fears, they became less and less agreed.  By this time nearly all the infantry had cleared the defile, when at daybreak a dense mist enveloped the whole defile and the neighbouring plains; which Hasdrubal perceiving, sent to Nero to put off the conference to the following day, as the Carthaginians held that day sacred from the transaction of any serious business.  Not even then was the cheat suspected.  Hasdrubal having gained the indulgence he sought for that day also, immediately quitted his camp with his cavalry and elephants, and without creating any alarm escaped to a place of safety.  About the fourth hour the mist, being dispelled by the sun, left the atmosphere clear, when the Romans saw that the camp of the enemy was deserted.  Then at length Claudius, recognising the Carthaginian perfidy, and perceiving that he had been caught by trickery, immediately began to pursue the enemy as they moved off, prepared to give battle; but they declined fighting.  Some skirmishes, however, took place between the rear of the Carthaginians and the advanced guard of the Romans.