Marginal vein
- Pronunciation
- /MAR-jih-nul vayn/
- Category
- Anatomy
- Singular
- marginal vein
- Plural
- marginal veins
Definition
In insect wing venation, a longitudinal running along or near the (costal) margin of the wing, typically formed by the fusion or thickening of veins near the wing edge. In Hymenoptera, the marginal vein is a specific, often enlarged section of the costal margin between the submarginal and the wing apex, formed by the fusion of the costal and radial veins; it is a critical diagnostic character for many , especially in such as and , where its relative length, thickness, and the position of break points (stigmal and postmarginal veins) distinguish and .
Etymology
From Latin 'marginalis' (pertaining to a margin) + 'vena' (), referring to its position along the wing margin.
Example
In the , the marginal is typically long and stout, often extending more than half the distance from the wing base to the apex, whereas in () it is shortened with the stigmal vein arising near its midpoint.
Synonyms
- costal margin (in part, when thickened)
- C+Sc+R (when costal, subcostal, and radius are fused)
Related Terms
- stigmal vein
- postmarginal vein
- submarginal cell
- costal vein
- radial vein
- wing venation
- pterostigma
- break point (wing)
- Hymenoptera
- Encyrtidae
Usage Notes
The term is most precisely applied in Hymenoptera, where 'marginal ' has a standardized meaning distinct from the general costal margin of other insect orders. In non-hymenopteran insects, 'marginal vein' may be used more loosely for any thickened vein. distinguish the marginal vein from the 'stigmal vein' (which bears the pterostigma or stigma) and the 'postmarginal vein' (when present beyond the stigma). The relative lengths of these three veins are key characters in chalcidoid . Some authors restrict 'marginal vein' to the portion basal to the stigma, while others include the entire thickened anterior margin; usage varies by and author.