Nothing is known of the criminal scientist known as the Insect Master prior to his appearance in Metropolis on a summer day in June 1943.  As citizens went about their affairs mid-day, the sky suddenly darkened as if a passing cloud.  As they watched the "cloud" descended, revealing itself to thousands of swarming insects outside the Daily Star.  Caught in the swarm, Lois Lane rushes inside as the insects depart as quickly as they arrived.  In the Editorial Office, she and Clark Kent are informed that a note as been received from "The Insect Master", claiming that he will make life unbearable with his insects unless he is paid tribute.

To emphasize his point, several other insect-induced catastrophes occurs.  A fur wholesaler's building is collapsed by the actions of thousands of termites and then the furs inside ruined by a swarm of moths.   Kent quickly changes into Superman and races to the scene, only to see the months flee.  He goes to work quickly on the collapsed building, rescuing those trapped in the rubble.  The job done, he flies back toward the Star and sees a swarm of locusts destroying the city gardens.  Using strength and super-speed, he crushes thousands of insect by hand to prevent further damage.  When he is finished, another swarm descends - wasps, hornets, and bees, stinging Superman and people nearby.  Superman infuriates the swarm and leads them to open water where he drowns them all before racing back to the gather up the stung victims and transport them to a nearby hospital. At the hospital, yet another swarm - this time of disease bearing flies - blows in and Superman quickly fend them off with clouds of menthol taken from the hospital formulary.

Initially, the Mayor refused to bow to the Insect Master's demands but a final swarm, wood chewing catepillars destroying Metropolis' main forest forces him to concede.  As his men drop off the ransom in Swasey Swamp, Lois Lane quietly follows.  She sees the Insect Master pick up the money but as she tries to follow, he doubles back out of sight and grabs from behind, taking her to his laboratory deeper in the swamp.   Clark Kent notices Lois' absence and suspecting her usual motives, learns the location of the drop off and flies there to check on her.  As Lois is left to the mercy of poisonous spiders, the Insect Master sees Superman's approach through video monitors and send projectiles rocketing into him, forcing him to land in quicksand.  As he sinks out of sight, the criminal scientist declares victory but is disappointed to learn Superman has tunneled under the earth, erupting through the floor to rescue Lois and take the battle to him.  Vowing to destroy them all, he activates self-destruct mechanisms through his laboratory consuming it in flames. Superman and Lois take flight, assuming they have heard the last of the Insect Master (World's Finest #10). 

Whether the Insect Master is dead or somehow survived to return another day has not been revealed..