"The Man in the Ant Hill", which spawned
Ant-Man, was
not Timely/Atlas/Marvel's first ant-themed tale...
...but I'm betting this never-reprinted tale from Adventures into Terror #43 (1950) is the first!
So there's elements of what would later be "Man in the Ant Hill" as well as the 1957 novella "The Fly" by George Langelaan, which became the basis for movie series in 1958 and 1986!
GCD attributes the art to Mike Sekowsky, but it
doesn't match his work on
Speed Carter: Spaceman only a couple of years later as shown
HERE,
HERE, and
HERE.
Either he radically modified his style within a very short timeframe (which is possible), or the guys at GCD got it wrong, which happens occasionally.
In any case, I'm going to stay with both the writer and artists of the story as "unknown", until somebody can provide proof otherwise.
Though this issue of Adventures into Terror was listed in the indicia as #43, it's actually the first issue since the book was previously-known as Joker Comics!
Apparently, the Post Office caught on, since by the third issue, the numbering was corrected to #3, indicting a new second class mailing permit had been issued.
The classic example of this sort of bait-and-switch by comics publishers to avoid paying for a new second class mailing license (which each periodical needed) was
EC's Moon Girl series.
The first issue was
Moon Girl and the Prince.
As of #2, it became just
Moon Girl.
When #7 came out, it became
Moon Girl Fights Crime, adding true-crime tales narrated by
Moon Girl. (The lead stories were still
Moon Girl adventures.)
Two issues later (#9), the book became a romance title,
A Moon, A Girl, Romance! (The final
Moon Girl story appeared in the back of #9.)
Finally, as of #13, the book shifted gears into science fiction and became
Weird Fantasy which ran from 13-17.
Then, since it had five issues under the
Weird Fantasy title, the Post Office forced
EC to buy a
new mailing permit for the series, and continue the numbering with #6.
It ran until #22, when it merged with
Weird Science into
Weird Science-Fantasy.
(This explains why
Weird Fantasy has
two #13, #14, #15, #16, and #17 issues a couple of years apart!)
Since
both Science and
Fantasy ended with #22, it's uncertain which series' mailing permit was used from that point until
Weird Science-Fantasy became
Incredible Science Fiction as of #30!
Got it?