Heterodiomus brethesi is a species of beetle of the family Coccinellidae. It is found in Chile.
Adults reach a length of about 1.4âÂÂ1.5 mm. Adults are pale reddish yellow, with the scutellar area of the elytron obscurely darkened.
The species is named for Jean Brèthes, the author of Heterodiomus and a significant figure in the classification of South American Coccinellidae.