The citation being "true" on its face is equivalent to the poor taxonomy option. That would mean that "pseudomantid" was a term used by orthopterists, and the writer of the Collier's article thought that "pseudomantids" were raphidopterans. In support of this interpretation, an Encyclopedia Americana article from 1951 say Raphidiodea have "the appearance of mantids". However, an entomologist would not normally use the word pseudomantid unless there were a family Pseudomantidae. There is no such family (only the tribe Pseudomantini), and there is no evidence that members of the genus Pseudomantis are called pseudomantids. On the other hand, I have not been able to find a raphidopteran genus beginning with "pseudo-", so there is no obvious word for "pseudomantid" to be an error for.
Perhaps the Collier's citation given is "true" on its face. Until all biologists who study those groups of insects have been polled, one would never know whether some few of them sometimes called those bugs pseudomantids. I'd be interested in what those few who study pseudomantid taxonomy and phylogeny would say about the usage.
The quotation is about Raphidiodea, which is now known as Raphidioptera, whereas Pseudomantis is part of Orthoptera. These are different orders of insects, so it is not true that raphidiodeans are sometimes called "pseudomantids". It's not clear what the error was: a malaprop, a misspelling, or poor taxonomy.
"With rather similar wings, biting mouth parts, and long antennae. Sometimes called pseudomantids. The larvae are predaceous and terrestrial or arboreal." - Collier's Encyclopedia: With Bibliography and Index, Volume 13, p.65, 1984.
Mollusque, I haven't been able to relocate the adjectival reference upon which I based my listing of pseudomantid - please accept the euvocalic plural noun pseudomantids, if you haven't done so already! Of course, Pseudomantis is well-attested.