Lema cyanella

{{Short description|Species of beetle}}

{{Speciesbox

| image = Lema cyanella1.jpg

| image_caption = Lema cyanella 4.0–5.5 mm

| taxon = Lema cyanella

| display_parents = 4

| authority = (Linnaeus, 1758)Linnaeus, C. 1758. Systema Naturae per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis, Tomus I. Editio decima, reformata. Holmiæ: impensis direct. Laurentii Salvii. i–ii, 1–824 pp

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}}

Lema cyanella, known as the californian thistle leaf beetle,{{Cite web |title=Californian thistle leaf beetle |url=https://www.landcareresearch.co.nz/discover-our-research/biodiversity-biosecurity/weed-biocontrol/projects-agents/biocontrol-agents/californian-thistle-leaf-beetle/ |access-date=2025-06-10 |website=Manaaki Whenua |language=en-US}}{{Cite web |title=Californian Thistle Leaf Beetle (Lema cyanella) |url=https://www.inaturalist.org/taxa/131816-Lema-cyanella |access-date=2025-06-10 |website=iNaturalist |language=en}} is a species of beetle in family Chrysomelidae.