The Boulder Snail was described in 1842; it inhabited the Clinch- and the Powell rivers which are a part of a river system that spans over parts of Georgia, Iowa and Tennessee, USA.
The species is now extinct, the last remaining population of this species disappeared when the Tellico River was dammed in 1979 to create Lake Tellico.
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The Boulder Snail is sometimes considered rediscovered, however, these accounts must be assigned to a closely related species, Anthony’s Boulder Snail (Athearnia anthonyi (Redfield)).
The Rocky Mountain Locust inhabited a large range., including Alberta, Manitoba, and Saskatchewan in Canada and Arizona, Colorado, Iowa, Kansas, Minnesota, Montana, Nebraska, North Dakota, Texas, and Wyoming in the USA.
The full-grown adults reached lengths of about 3 cm.
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The species formerly formed seasonally swarms of giant sizes, which then devastated large areas of North America, destroying countless crops, and causing famines.
It is said that the locust plague did not spared cotton clothing or leather when found, and it is furthermore claimed, that they may have even eaten wooden fencing posts.
These last assertions, however, are probably pure fantasy.
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The last large swarms were recorded in the years between 1873 and 1877, the last specimens were finally collected in Manitoba, Canada in 1902.
The reasons for the extinction of this once so common species are not well known, but it has been argued that plowing and irrigation by settlers in the Great Plains disrupted their natural life cycle in the areas they lived in, so it is reported that farmers destroyed over 150 egg cases per square inch while plowing, harrowing or flooding. [1]
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References:
[1] Jeffrey A. Lockwood: Locust: The Devastating Rise and Mysterious Disappearance of the Insect that Shaped the American Frontier. New York: Basic Books 2004
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malefemales laying eggs growth stages
Depictions from: ‘Francis Huntington Snow: The more destructive grasshoppers of Kansas. University of Kansas Bulletin of the Department of Entomology (Topeka, KS: J. S. Parks, October 1897)’
This species was described in 1924 based on a single male specimen; it is, however, thought to be a misidentified specimen of another species, the Colorado Prominent (Heterocampa rufinans (Dyar)).
The sole specimen needs a revision, if it turns out to represent indeed a distinct species (which is rather unlikely), then it is most likely extinct.
