I think the needle/sting is no more than a delivery system. Because if you look at snakes, they have venom sacks and when they attack, their fangs serve as a delivery system rather than both the production and the delivery.

If you compare it to a syringe injection, a bee/wasp sting probably works the same way.

And for the neutralisation reaction, it might not work since the pH value of the two are different. Bee venom: 5.0-5.5 and Wasp venom:6.8-6.9.

http://www.insectstings.co.uk/sting-acid-or-alkali.shtml

And if you read this, you will see that a neutralisation reaction is less likely to occur even with acid(for wasps) and alkali(for bees).

Is the venom that bees and wasps carry produce inside the sting, or is the sting only a delivery system of the venom? Also, is it true that bees and wasps have different ph's of their venom, as in ones acidic and ones alkaline? (simply curious as i heard a person say you could technically neutralize one with the other, which i know is probably feasible but would be highly impractical) You ask whether the venom is in the sting, but the question is slightly ambiguous. If a bee stings you properly then it will leave behind its stinging apparatus, which will stick out of your skin like a little bulb at the end of a tiny shaft. The real sting is a minute sliver inside that shaft, and it contains no poison to speak of; it is like the needle of a hypodermic syringe, only tens or hundreds of times smaller. People think that the bulb is the bag of poison, but it is not; it is a very complex structure of glands and pumps. You hear warnings not to squeeze it, but to get a blunt knife to scrape it off. Rubbish! The structure is far too complex to squeeze much poison out of. Blunt knives are good, certainly, but only if they are immediately available. The longer it sits the more venom it can pump in. Just get it out of the skin by any means possible, as quickly as possible, squeezing or no squeezing. Leave the rest for old wives to weave their tales over and backyard experts to bicker over.

As for acidity or alkalinity, ignore that. The venoms are mixes of poisonous proteins, generally enzymes that damage tissues and nerve cells, and other enzymes that help them penetrate your tissues; their pH is not many points off neutral and have nothing to do with their effect. Wasps of thousands of kinds and bees have various kinds of venoms, though generally fairly closely related, but none of them is likely to have any neutralising on any other.

On a slightly different note though, an old beekeeper I once knew was practically immune to stings, but when he accidentally got stung by a local paper wasp he reacted immediately and very nearly died!