Beetle vs Bug

Beetle

noun

  • A small car, the Volkswagen Beetle (original version made 1938–2003, similar models made 1997–2010 and since 2011). 

Bug

noun

  • A Volkswagen Beetle car. 

  • A Bugatti car. 

name

  • A river flowing northwest 450 miles between Belarus and Poland. 

  • A river in Ukraine (Southern Bug), flowing 530 miles to the Dnieper estuary. 

How often have the words Beetle and Bug occurred in a corpus of books? (source: Google Ngram Viewer )