Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
(unranked): clade Heterobranchia
(unranked): clade Euthyneura
(unranked): clade Panpulmonata
(unranked): clade Eupulmonata
(unranked): clade Stylommatophora
(unranked): informal group Sigmurethra
(unranked): clade limacoid 
Superfamily: Limacoidea
Family: Limacidae
Subfamily: Limacinae
Genus: Ambigolimax
Species: A. valentianus
Binomial name: Ambigolimax valentianus
Synonyms: Lehmannia valentiana, Limax valentianus, Limax valentiana, Limax poirieri, Limax marginatus.
Common name: Striped greenhouse slug, Three band garden slug, Greenhouse slug, Spanish slug, Hothouse alien, Striped Field Slug

Ambigolimax valentianus is a species of air-breathing nocturnal land slug that is native to Spain and Portugal.
It is a synanthropic slug that has been introduced to disturbed habitats worldwide. This introduced species of air-breathing land slug is found throughout New Zealand.
It is a translucent brownish slug with darker mantle bands. Two bands are usually prominent; one on either side of the body’s midline, but the lower third pair of bands may be faint. The mantle has multiple fingerprints like pattern ridges. The sole is pale and unicolourous in this species. The breathing pore (pneumostome) is located on the right, in the posterior third of the mantle. Mature adults can grow to a length of about >75 mm.
This slug produces copious amounts of slime as a defence mechanism. The oval eggs produced by this species are yellow and measures 2.25 mm wide. There may be as many as 60 eggs per clutch.
They live moist habitats and consume decaying organic matter and living plant material. It is a serious pest in greenhouses. It is also found in plant nurseries, allotments, under dead wood and in compost bins.

Three band garden slug Lehmannia valentiana-001.JPG  

Three band garden slug Lehmannia valentiana.JPG 

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