Entomology definition of Third longitudinal vein September 14, 2014 Raj Entomology Dictionary 0 Please Like Us!!! DesiGoogly.com > Education News > Entomology Dictionary > Entomology definition of Third longitudinal vein Entomology definition of Third longitudinal vein: in Diptera (Will.):= radius 5 (Comst.). Entomology Third longitudinal vein definitionThird longitudinal vein Entomology explanationThird longitudinal vein Entomology meaningReviews & Comments