The picnic fly is among the most vexing creatures ever created by the Almighty. While it is indubitably true that He moves in mysterious ways His wonders to perform, it baffles the brain to wonder what moved Him to move in such a way that He felt inspired to think up, fashion, and let loose upon the world the picnic fly.

There is a body of opinion that the picnic bee, picnic wasp, and particularly the swarm of picnic hornets are more vexing than the picnic fly. Bee, wasp, and hornet, runs the argument, have tiny pointy envenomed protuberances with which they can sting any patches of bare flesh paraded by a picnicker, sometimes, though not often, resulting in an agonising death. The picnic fly, on the other hand, is by comparison harmless. This argument carries much weight, and even as I write I find myself wondering how it can be that I can possibly justify a claim that the picnic fly is the more vexing flying beastie. But I shall plough on regardless of common sense. That is my way.

Picnic flies usually go about in small swarms. They will hover in the air, at about human adult head height, at something of a loose end, awaiting the arrival of a brake containing picnickers with their picnicking appurtenances. Upon the arrival of the brake in the buttercup-dappled meadow by the gurgling brook, the picnic flies will disperse upon the air, temporarily. They do this because no picnicker in their right mind would lay the picnic blanket on ground immediately below a hovering swarm of picnic flies.

Note : this is not to say that all picnickers are necessarily in their right minds. Some are deranged or otherwise have dislodgements of the brain which cause them to make foolish picnic decisions. The terms “picnic fool” or “picnic fathead” have been coined to describe such persons. Neither are terms which should be bandied carelessly about. It is advisable to be on firm ground when uttering the charge.

Each picnic fly will now watch carefully as the preparations for the picnic are made by those who tumble out of the brake. Timing, for the picnic flies, is of the essence. They will not reconvene, forming a hovering swarm at human adult head height over the picnic, until it has been fully assembled. Thus, the picnic blanket is laid out and, if there is a hint of wind, stones will be collected to weigh down the corners. Folding chairs may be unfolded and placed around the blanket for the elderly, the infirm, or the picnic-inexperienced. The hamper or hampers will then be removed from the brake, and the contents arranged upon the blanket. In addition to cups and beakers and plates and saucers and bowls and dishes and cutlery, cutlery, cutlery, there will be sausages and pies and fruits of various kinds and bloater paste sandwiches and flans and tarts and Laughing Cow foil-enwrapped cheese triangles and biscuits and trifle and marmalade and pickled onions and butter and roll-mops and salads and iced buns and sliced cold meats and pastries and boiled eggs and chocolate buttons and boiled sweets and toffee and pork scratchings and puddings and potato snacks and soup in flasks. Other flasks will contain tea, and there will be lemonade and wine and Tizer and dandelion-and-burdock and beer and sherry and cans of Squelcho!. Depending on the picnic demographic, there may also be laid out, near to but not on the blanket, tennis racquets and tennis balls and medicine balls and the appropriate kit for sword-fights, archery contests, and hammer-throwing.

Within seconds of the last item being laid out and each picnicker sat or sprawled, the swarm of picnic flies will suddenly reappear, hovering directly over the picnic blanket. Taking their turns, a few flies at a time will separate from the swarm and make darting flights down towards the blanket, where they will plod on their tiny suckered feet across, say, the icing on an iced bun. They will regurgitate some sort of godawful gack from their innards on to the icing, then suck it, together with a modicum of the icing, back up into their tiny but ravenous fly’s maw. Momentarily sated, this grouplet of picnic flies will return to hovering-height, and another contingent will descend.

It is important to note two things about the activity described. First, that it all takes place in a matter of a few seconds, if that. Also, that flies are pretty tiny, as well as quick, so the disgusting business with the regurgitation and the sucking is not generally visible to the unassisted eye of the picnicker. What usually happens is that one of the picnickers – it may be a chap with a decisive moustache and a blazer and cravat – flails his arms in an attempt to swat the fly. Unfortunately, by the time the chap’s brain has sent the signal to his arm to flail, the fly will have done its unseemly feeding and be halfway back to the hovering swarm. I told you they were quick. And because the unseemly feeding is not apparent to the unassisted picnicking eye, what then happens is that another picnicker – it may be a demure young lady in a bonnet, clutching a slim volume of twee verse, or a bluestocking with a thick hefty book of intractable German philosophy – will pick up the iced bun with her free hand and take a dainty bite from it. Along with bun and icing, she will then of course swallow what remains of the picnic fly’s godawful gack, that part of it which it did not suck back into its maw.

I would argue that this is precisely why the picnic fly is the more vexing. At least you know where you are with a bee or a wasp or a hornet, singly or in swarms. If they cannot be swatted away, and a picnicker is stung, then the first aid kit can be fetched from the glove compartment of the brake, and salve and bandages applied. As I said, agonising death is rare, and basic cosseting will usually be all that is required. The picnic flies, being smaller and quicker and more determined than bees, wasps, and hornets, will be as near as dammit impossible to swat away, and their predations of the sausages and pies and fruits of various kinds and bloater paste sandwiches and flans and tarts and Laughing Cow foil-enwrapped cheese triangles and biscuits and trifle and marmalade and pickled onions and butter and roll-mops and salads and iced buns and sliced cold meats and pastries and boiled eggs and chocolate buttons and boiled sweets and toffee and pork scratchings and puddings and potato snacks will be all the more relentless. Each and every picnicker will climb back into the brake with a small amount of godawful gack in their stomachs, or lodged in their gums, with who knows what dastardly eventualities.

The best one can hope for is that at least some of the picnic flies will be fated to drown in the soup or tea or lemonade or wine or Tizer or dandelion-and-burdock or beer or sherry or, if they manage to negotiate the narrow opening in the lid, the cans of Squelcho!.