Img 1 Picture of cat flea (Ctenocephalides felis) eggs on a finger tip.
Cat flea eggs are 0.5 mm long and 0.3 mm wide. Though minute, they’re still large enough to be seen by the unaided eye. The eggs are a rounded ovoid shape. They’ll appear a translucent white color when freshly deposited, but turn slightly more opaque and pearl-like as they age. Flea eggs are often said to look like tiny pearls, salt grains, or dandruff flakes.
Eggs of the cat flea are very small. They measure 0.5 mm in length, and 0.3 mm in width. Though tiny, the eggs can be seen by the naked eye. For comparison, a sharp #2 pencil’s tip is around 1 mm Img 2, and a grain of table salt is 0.3 by 0.3 mm.
Img 2 Illustration showing the size of a cat flea egg compared to the tip of a sharp #2 pencil (1 mm).
Freshly laid flea eggs are shiny, semi-transparent, and colorless to white Img 1. As they age and embryonate, the eggs become slightly darker and more opaque, taking on a pearly-white color. Prior to hatching, larvae are visible through the eggs’ semi-transparent shells.
The white flea eggs can be difficult to see on light-colored fur or fabric. Thus, placing a piece of dark cloth or paper beneath the eggs can make them more visible.
Shape & Stickiness
Flea eggs are an elongate oval shape with two rounded ends. Viable eggs have a smooth surface with no indentations. Non-viable or insecticide-exposed eggs will be dimpled or collapsed. Flea eggs are initially wet and sticky when they’re deposited, but they dry rapidly. Within a few hours, the dry eggs readily fall from where they’re laid on a host.
Flea egg chorions (outer shells) are simple and smooth. They lack the surface structures and patterns which are common of other insect eggs. The chorion only contains micropyles and aeropyles, which allow for the entrance of sperm and exchange of gas. These are clusters of small pores found at the egg’s poles.
Cat flea eggs are more fragile than those of other insects. The chorion has an amorphous gel-like structure. It’s single-layered and only 1 picometre thick. A thin protective layer of material called spumaline gets secreted onto the eggshell when it’s laid. The spumaline membrane may serve to repel water and prevent water loss, since flea eggs don’t have a wax coating.
Similar in Appearance
Due to their size, color, and translucency, flea eggs are often described as looking like grains of salt or tiny pearls. When identifying fleas, it’s recommended to look for salt and pepper on pets. The salt refers to the white eggs, and the pepper refers to the reddish-black feces (flea dirt).
Flea eggs are also described as resembling grains of sand, granules of sugar, flakes of dandruff, or miniature china eggs. Under a microscope, flea eggs look like white jelly beans. Accumulations of eggs have the appearance of fine sprinklings of sugar.