The Vega company is probably best known today for its vintage banjos, but it also made a variety of mandolins (including the famous "cylinder-back" model), and was either the third or fourth major manufacturer to produce an electric one. According to renowned guitar collector Scott Chinery, Vega introduced its electric mandolin in 1936, the same year as the Gibson EM150. Vega electrics are quite rare, and the company experimented with different body styles, as well as several types and configurations of pickups, as you can see from the photos here. The black mandolin below features a Rickenbacker-style horseshoe pickup and is one of 100 that were sold with matching amps. Below that, the mandolin on the left is definitely a Vega, and while the pickup might be a factory installation, surely those chickenhead knobs are later replacements. The one with no soundholes on the right was represented to me as a 1955 Vega, but like Montresor I have my doubts. See Scott Chinery's book The Chinery Collection for yet another photo.