In his book Why Not Eat Insects? Vincent M. Holt  does not confine himself to this group of invertebrates. In addition to remarks about slugs and snails, he also has this to say:
..Spiders have been relished as tid-bits, not only by uncivilized nations, but by Europeans of cultivation. For Reaumur tells of a young lady who was so fond of spiders that she never saw one without catching and eating it. Lalande, the French astronomer, had similar tastes; and Rosel speaks of a German who was in the habit of spreading spiders, like butter, upon his bread.
Spiders are chelicerates and, had Holt travelled to China, Thailand or Vietnam he would have been aware of other chelicerates, scorpions, being eaten, often as “street food”. Scorpions have a sting that is used to inject venom but, when cooked, the venom becomes denatured and the whole animal can be eaten. A common method of preparation is to line scorpions on skewers that can then be grilled (see below), or they can be stir fried. Those who eat scorpions compare their flavour to
that of crabs, or shrimps, and scorpions are rich in protein, so provide a readily available and nutritious food .
The largest chelicerates, the eurypterids, became extinct about 250 million years ago, so there is no possibility that they co-existed with humans, or close human ancestors. However, just as we like to imagine co-existing with reptilian dinosaurs (equally impossible), it is fun to think what our attitude to eurypterids would be should they still be present today.
In the image above, adapted from an illustration in a paper by Braddy, Poschmann and Tetlie  we see the body form of the eurypterid Jaekelopterus. It is typical of the “sea scorpions” in having four pairs of walking legs, chelicerae (limbs with claws), a pair of paddles and a segmented body ending in a flattened extension. Two compound eyes are present and, in a comparative study of the fossilised remains of eurypterids of several types, it is concluded that Jaekelopterus was likely to be an active predator and that competition with more successful vertebrate types led to its extinction , alongside all the other eurypterids.
The location of fossils shows that Jaekelopterus lived in “marginal marine environments”  so, had these creatures survived to modern times, they would have been easily accessible to humans and, no doubt, would have been made extinct by human hunting. At this point, we need to consider the size of the animals: the scale bar in the illustration shows 1 metre, so specimens of Jaekelopterus were up to 2 metres long and thus substantially longer than the average human (2 metres being equivalent to 6 feet 6 inches). If their chelicerae were disabled, they would be easy to catch and they did not have the defensive sting present in today’s scorpions (they are not closely related).
Letting our imagination free, we can fantasise that Jaekelopterus, with its long and muscular body, would be good to eat, especially when prepared using the cooking skills of modern humans – “eurypterid thermidor” anyone? Nonsense of course, but what fascinating creatures they must have been, had we been able to observe them.
 Vincent M. Holt (1885) Why Not Eat Insects? Faringdon, E.W.Classey Ltd.
 S. J. Braddy, M. Poschmann and O. E. Tetlie (2008) Giant claw reveals the largest ever arthropod. Biology Letters 4: 106-109.
 V. E. McCoy, J. C. Lamsdell, M. Poschmann, R. P. Anderson and D. E. G. Briggs (2015) All the better to see you with: eyes and claws reveal the evolution of divergent ecological roles in giant pterygotid eurypterids. Biology Letters 11: 2015.0564.