The colloquial noun beetle-crusher denotes a foot or a boot, especially a big one.

Curiously, in four of the five texts containing the earliest occurrences of beetle-crusher that I have found, the noun is applied to ladies’ feet and ladies’ boots.

These texts are:

1-: The caption to the following cartoon by John Leech (1817-1864), published in Punch, or the London Charivari (London, England) of Saturday 4^th October 1856—tootsicum is a playful or endearing name for a child’s or a woman’s small foot:

SHOCKING RESULT OF WEARING INDIAN-RUBBER GOLOSHES ON THE SANDS.

Young Jack Robinson sees what he imagined to be the Impression of his Darling’s Foot—He mentally ejaculates, “Beetle-crusher,* by Jove!” and flies to other climes.
* A vulgar and disgusting expression, implying that a foot is big enough, and flat enough, to kill Black-beetles. The brutality of connecting in any way such words with the feminine Tootsicums, needs no comment.

2-: The following from Punch, or the London Charivari (London, England) of Saturday 7^th February 1857:

METROPOLITAN FANCY BLACK-BEETLE CLUB.

The third “Session” of this Club was celebrated on Wednesday last by a dinner at Crickett’s Hotel, Grasshopper Lane, City, when a numerous attendance of members took place. Mr. Paul de Cockroche, the President, occupied the chair, faced by Mr. Bugsby, the Honorary Secretary.
[…]
A Member said that it was a cheering fact that no more opprobrious epithet could be bestowed upon a lady’s feet than to call them beetle-crushers. (Laughter and cheers.)

3-: The following from The Islington Gazette (London, England) of Saturday 26^th September 1857:

Choosing between evils is always a melancholy necessity. There is nothing intrinsically pleasant in saving one’s eyes at the expense of one’s feet, and it consoles a lady but little when her anything but beetle-crushers are smothered in mud and her laced petticoat rendered—miserabile dictu—“not fit to be seen,” to remind her that, but for the cause of these misfortunes, she would have been half choked and entirely blinded by dust.

4-: A letter by a certain John ap John, published in The Field, the Farm, the Garden, The Country Gentleman’s Newspaper (London, England) of Saturday 15^th January 1859:

CORNS.—[…] For years I had been a sufferer from these painful excrescences, and have long arrived at the conclusion, that the usual weak-minded system of conforming to fashion in the make of boots and shoes—narrow toes to wit—is the sole cause of their origin. Of late years I have entirely set aside the services of the “swell bootmaker” (who, by the by, never would fit me as I desired), and now resort to the ready-made emporium, where, amidst some hundreds of pairs and patterns, I can try on and fit to my liking. If any of your readers afflicted with corns will sacrifice fashion and pain to ease and comfort, let them follow my example; and although their cramped up, “light fantastic toes” may swell into the ample proportions of respectable-looking “beetle-crushers,” they will not fail to bless the day on which they became converts to a system which will surely release them from their disagreeable tormentors.

5-: The review of Sparks from a Locomotive; Or, Life and Liberty in Europe (New York: Derby & Jackson, 1859), by the U.S. journalist and educator Hiram Fuller (1814-1880)—review published in Bell’s Weekly Messenger (London, England) of Saturday 17^th September 1859:

We must say this for the Colonel, that if he is ungallant in one or two instances, he makes up for it by his compliments to the good taste which English women show in dress; to their wisdom in seeking health for themselves and their children in the open air; and to the magnificence of their personal charms. This, however, we fear, will be no compensation for the libel upon feet. The Colonel was in England in the winter months, when “beetle crushers” are in use, than which nothing more effectually deforms the female foot.

This is the relevant passage from Sparks from a Locomotive; Or, Life and Liberty in Europe—Hiram Fuller does not use the noun beetle-crusher in his book:

It is very evident that a large foot is not considered a detriment to female beauty in England; as the ladies make no effort to diminish the size of their feet by wearing pinching slippers. On the contrary, they wear clumsy gaiters, with heavy soles, which make their steps anything but fairy-like. And in this they show their good sense. One half of the consumption cases among the American women are owing to wafer-soled shoes, which render walking both difficult and dangerous. And so they sit pining in satin chairs in their over-heated rooms, sucking cough candy, and waiting for the doctor, and his shadow the undertaker; while these buxom English beauties are tramping about in their water-proof boots, or darting through lanes and parks in their saddles. To appear delicate or lackadaisical is no part of an English woman’s ambition. Health and vigor of body are considered of primary importance, not only for comfort’s sake, but as the most essential qualifications for satisfactorily and successfully performing the duties of wives and mothers.

The following definition is from The Slang Dictionary; or, The Vulgar Words, Street Phrases, and “Fast” Expressions of High and Low Society. Many with Their Etymology, and a Few with Their History Traced (London: John Camden Hotten, 1864):

BEETLE-CRUSHER, or SQUASHER, a large flat foot. The expression was first used in one of Mr Leech’s caricatures in Punch.

The noun beetle-crusher gave rise to the adjective beetle-crushing—as in the following from Edinburgh Gossip, published in The Perthshire Journal, and Constitutional (Perth, Perthshire, Scotland) of Thursday 29^th December 1870:

The female students still attract a little attention, but not much. At first crowds used to gather round the College gates to see them. I believe they were popularly supposed to be some nondescript species of monster; to wear—well, Bloomers, and that sort of thing; but no! they were undoubted specimens of femininity, be-chignonned, and be-panniered like their neighbours; plain certainly, and with a strong tendency to a beetle-crushing developement, but otherwise harmless; and so they now go on their way almost unnoticed. Even their body-guard has left them. The hooting and pelting with mud was undeniably bad, and was done by a set of roughs, but that corps-de-garde was a rougher set still.