“Crawlers” was published in Imagination in July 1954. It can be found in Second Variety and Other Classic Stories by Philip K. Dick in pp. 167–173.
A crawler is enjoying a construction project. It is underground, visible from the surface only as a mound of clay.
A farmer is driving Ernest Gretry through a rural community. They stop before a crawler, killed by cars on the road. It looks like a long snail, with a formed head and a human-like face (hard to look at), but a malformed, worm-like body. The farmer explains that they often crawl across there and are not infrequently run down by teenagers. He mentions that one has been preserved in kerosene at the filling station. These crawlers are the only children being born now. Almost no normal children are born. People are beginning to move away.
Gretry called his supervisor to report on the situation. Gretry recommends moving the people away from the radiation zone around the lab that seems to be causing the mutation. The “crawlers” should be collected and transported to an island previously used for nuclear tests. After the call, Gretry notices that the town is dying without the sounds of children playing. During a trip into town, a cab driver explains to Gretry that the crawlers are building houses underground and that they have an entire city. They seem to be dangerous too. They have a stinger and killed at least one dog. They arrive at Mr. Higgins farmhouse, which is where the crawlers having been building their “city.”
Gretry discusses the situation with an old woman at the Higgins farmhouse. He explains that the government wants to remove the crawlers but since they are legally the children of the townspeople, there are legal problems. The old women shows Gretry a young couple holding a carton containing a one-month-old crawler. They eat grass and leaves. The father explains how he saw one of the first of these destroyed by Bob Douglas, who smashed its head with a rock and burned it to death. Gertry tells them that he will order the collection and removal of all the crawlers.
On an island, crawlers are busy building their networked city. They are expanding beyond the island through underground networks. Unfortunately, many of the newborn children are turning out to be “throwbacks” with arms and legs. These anomalies are immediately killed.
What the reader of “Crawlers” may immediately notice is that the moral attributes of the crawler—human offspring mutated by exposure to radiation—are very similar to those of humans. Like humans they have an intense desire to build communities, are very protective of their creations, and ultimately fearful other physical otherness. They are certainly monstrous looking to the human women who give birth to them and it is not clear what role they could play in human society, but they are not entirely alien. Perhaps it is that they are close enough that makes them so terrifying.
The government approach to the crawlers is simply to try to exile them from sight. They are essentially a bureaucratic problem, no more difficult to solve than any of the other relocations that make up so much of twentieth century history. From the internment of Japanese, to the depopulation of Pacific islands for nuclear testing, to the crimes of the Holocaust, by the time Dick was writing governments were expert at relocating populations unwillingly. The decision to move the people of the town away from the radiation and then the crawlers to an abandoned island, is morally offensive but a perfectly logical solution to the problem. Even the people of the town are eager for this solution, it if can remove from sight the monstrosities that have invaded their quiet lives. The trouble is that once removed from the radiation, the crawlers begin to have “thrown-back” children. The problem repeats itself. (Maybe someday the grandchildren of the townspeople can be returned to human society, but for the time being they are unwanted, unnecessary, and horrifying to the crawlers0>
The story was likely inspired by horror stories coming out while Dick was writing about the biological effects of radiation. I posted some links about this below.
Wikipedia post on “Crawlers.”