In the uncertainty of identifying these four creatures, it has been suggested that some of the names may belong to locusts in an imperfect state of development. Most modern versions have taken a safer course than our translators, by retaining the Hebrew names.

The locust - ארבה arbeh, either from ארב arab, to lie in wait or in ambush, because often immense flights of them suddenly alight upon the fields, vineyards, etc., and destroy all the produce of the earth; or from רבה rabah, he multiplied, because of their prodigious swarms. See a particular account of these insects in the notes on Exodus 10:4 (note).
The bald locust - סלעם solam, compounded, says Mr. Parkhurst, from סלע sala, to cut, break, and עם am, contiguity; a kind of locust, probably so called from its rugged, craggy form. See the first of Scheuchzer's plates, vol. iii., p. 100.
The beetle - חרגל chargol. "The Hebrew name seems a derivative from חרג charag, to shake, and רגל regel, the foot; and so to denote the nimbleness of its motions. Thus in English we call an animal of the locust kind a grasshopper; the French name of which is souterelle, from the verb sauter, to leap" - Parkhurst. This word occurs only in this place. The beetle never can be intended here, as that insect never was eaten by man, perhaps, in any country of the universe.
The grasshopper - חגב chagab. Bochart supposes that this species of locust has its name from the Arabic verb hajaba to veil; because when they fly, as they often do, in great swarms, they eclipse even the light of the sun. See the notes on Exodus 10:4, and the description of ten kinds of locusts in Bochart, vol. iii., col. 441. And see the figures in Scheuchzer, in whose plates 20 different species are represented, vol. iii., p. 100. And see Dr. Shaw on the animals mentioned in this chapter. Travels, p. 419, etc., 4th. edition; and when all these are consulted, the reader will see how little dependence can be placed on the most learned conjectures relative to these and the other animals mentioned in Scripture. One thing however is fully evident, viz., that the locust was eaten, not only in those ancient times, in the time of John Baptist, Matthew 3:4, but also in the present day. Dr. Shaw ate of them in Barbary "fried and salted," and tells us that "they tasted very like crayfish." They have been eaten in Africa, Greece, Syria, Persia, and throughout Asia; and whole tribes seem to have lived on them, and were hence called acridophagoi, or locust-eaters by the Greeks. See Strabo lib. xvi., and Pliny, Hist. Nat., lib. xvii., c. 30.

[Even] these of them ye may eat; the locust after his kind, and the (f) bald locust after his kind, and the beetle after his kind, and the grasshopper after his kind.
(f) These were certain types of grasshoppers, which are not now properly known.

Even these of them ye may eat, &c. The four following ones, which seem to be no other than four sorts of locusts:
the locust after his kind; this is the common locust, called by the name of Arbeh, from the great multiplication and vast multitudes of them; the phrase, "after his kind", and which also is used in all the following instances, signifies the whole entire species of them, which might be eaten:
and the bald locust after his kind; which in the Hebrew text is Soleam, and has its name, as Aben Ezra suggests, from its ascending rocks: but since locusts do not climb rocks, or have any peculiar regard for them, rather this kind of locust may be so called, from their devouring and consuming all that come in their way (g), from the Chaldee word which signifies to swallow, devour, and consume; but why we should call it the bald locust is not so clear, though it seems there were such, since the Jews describe some that have no baldness, which the gloss explains, whose head is not bald (h), which shows that some are bald; and so, this is described by Kimchi (i), it has an eminence, a rising, or bunch upon it; some render it baldness, and it hath no tail, and its head is long; and so Ben Melech:
and the beetle after his kind; which is another sort of locust called Chargol, and should not be rendered a beetle, for no sort of beetles are eatable, nor have legs to leap withal, and so come not under the general description given of such flying, creeping things, fit to eat: Kimchi says it is one kind of a locust (k), and Hiscuni derives its name from and because it strives to leap with its feet, which answers to the above descriptive character: the Septuagint and Vulgate Latin versions, and some others, render it by Ophiomachus, a fighter with serpents, to which the locust is an enemy, and kills them, taking fast hold of their jaws, as Pliny says (l), and so Aristotle (m):
and the grasshopper after his kind; this is another, and the fourth kind of the locust that might be eaten; its name is Chagab, from the Arabic word Chaguba, "to vail", locusts vailing the light of the sun: and according to the Jewish doctors, it is a name which every locust fit to eat should have;"among the locusts (fit for food) are these, who have four feet, and four wings and thighs, and wings covering the greatest part of them, and whose name is Chagab (n);''and commentators say (o), it must be called by this name, as well as have those signs: the difference between these several sorts is with them this; the Chagab has a tail, but no bunch; Arbeh neither bunch nor tail; and Soleam has a bunch, but not a tail; and Chargol has both bunch and tail (p): Maimonides (q) reckons up eight sorts of them fit to eat; and these creatures were not only eaten by the Jews, but by several other nations: with the Parthians they were very agreeable and grateful food, as Pliny (r) relates; who also says (s), that some part of the Ethiopians live only upon them all the year, hardened in smoke, and with salt: Diodorus Siculus (t) makes mention of the same, and calls them Acridophagi, locust eaters, and gives a particular account of their hunting and taking them, and preserving them for food; and so does Strabo (u); and the same Solinus (w) relates of those that border on Mauritania; and they are still eaten in Barbary, where they dry them in ovens to preserve them, and then either eat them alone, or pounded and mixed with milk: their taste is said to be like shrimps (x); and Bochart (y) has shown, from various writers, that they were a delicious food with the Greeks, especially among the common people; and so they are with the Indians (z).
(g) So R. Song. Urbin. Ohel Moed, fol. 88. 1. (h) T. Bab. Cholin, fol. 65. 2. (i) Sepher Shorash. in voc. (k) Ib. in voc. (l) Ut supra. (Nat. Hist. l. 11. c. 29.) (m) Hist. Animal. l. 9. c. 6. (n) Misn. Cholin, c. 3. sect. 7. (o) Maimon. & Bartenora in ib. (p) Vid. T. Bab. Cholin, fol. 65. 2. (q) Maacolot Asurot, c. 1. sect. 21. (r) Nat. Hist. l. 11. c. 29. (s) Ib. l. 6. c. 30. (t) Bibliothec. l. 3. p. 162, 163. (u) Geograph. l. 16. p. 531. (w) Polyhistor. c. 43. (x) Sir Hans Sloane's Natural History of Jamaica, vol. 1. p. 29. (y) Hierozoic. par. 2. l. 4. c. 7. col. 490, 491. (z) Agreement of Customs of the East Indians and Jews, art. 12. p. 60.

The locust - Locusts, though unusual in our food, were commonly eaten by the Ethiopians, Lybians, Parthians, and other eastern people bordering upon the Jews. And as it is certain the eastern locusts were much larger than ours, so it is probable they were of different qualities, and yielding better nourishment.