The stellar content of two OB associations in the LMC - LH 117 (NGC 2122) and LH 118

Photometry for stars in two adjacent OB associations in the LMC, numbers 117 and 118 in the list of Lucke and Hodge (1970), is presented. Each association contains about 50 stars with mass larger than 10 solar, including two newly confirmed red supergiants. Most of the stars in these associations are in the first half of their lives on the main sequence. However, the two red supergiants and a B2 I stars are of lower mass than several of the unevolved, more massive members of the associations, and must have formed six to 10 million yr earlier than most of the association members. The initial mass function of the associations has a slope of - 1.8, similar to the one observed for massive stars near the sun