Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Superfamily: Limacoidea
Family: Limacidae
Subfamily: Limacinae
Genus: Limax
Subgenus: Limacus
Species: L. flavus
Binomial name:  Limacus flavus
Synonyms: Limax flavus, Limax variegatus, Limacella ungicula, Limax megaldontes, Limax umbrosus, Krynickillus maculatus, Limax olivacius, Limax erenbergii, Krynickia maculata, Limax deshayesi, Limax companyoi, Limax breckworthianus, Limax beaticus.
Common names: Yellow slug, Tawny garden slug, Cellar slug.

 Limacus flavus is a medium to large species of air-breathing land slug accidentally introduced to New Zealand and many other parts of the world.
Limax flavus has a yellow body with greyish-green mottling covering the entire body. The oval mantle has ridges that appear as a fingerprint pattern. The pneumostome (breathing pore) is located behind the midline of the mantle and is surrounded by a halo. The sole of the foot is yellow-white. It has distinctive pale blue optical tentacles. When extended, the body length can be 75 to 115 mm. This species feeds mostly on fungi, lichen, decaying matter and plant material. It is nocturnal, feeding at night. During the day its habitat is moist dark places. It can lay up to 140 odd 6 mm eggs.

Limax flavus Yellow slug-004.JPG

Limax flavus Yellow slug.JPG

Limax flavus Yellow slug.JPG

The distinctive blue coloured optical tentacles.
Limax flavus Yellow slug-003.JPG

The fingerprint pattern on the mantle
Limax flavus Yellow slug-008.JPG

Limax flavus Yellow slug-004.JPG 

Limax flavus Yellow slug-006.JPG

Limax flavus Yellow slug-001.JPG

A juvenile slug
Limacus flavus.JPG

6 mm slug eggs found in the same areas as the above slugs. The developing slugs can be seen within the eggs.
Slug eggs 5mm dia.JPG 

Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/