- Found on any giant mantis variety, including giant mantis nymph and mantis ootheca.
- Found randomly inside Goodsprings schoolhouse in multiple mantis ootheca.
- Found inside Vault 22 in the cave section of Pest Control, right near Keely, inside multiple mantis ootheca.
- A pile of giant mantis egg can also be found in Vault 22, as part of the quest Bleed Me Dry.
- While there are two varieties of the egg, only one of them is obtainable without use of console commands. The other kind is tagged as a quest item, has 0 value and 0 weight.