This paper studies the computational complexity of the proper interval colored graph problem ( PICG ), when the input graph is a colored caterpillar, parameterized by hair length. In order prove our result we establish a close relationship between the PICG and a graph layout problem the proper colored layout problem ( PCLP ). We show a dichotomy: the PICG and the PCLP are NP-complete for colored caterpillars of hair length ≥ 2, while both problems are in P for colored caterpillars of hair length 2. For the hardness results we provide a reduction from the multiprocessor scheduling problem , while the polynomial time results follow from a characterization in terms of forbidden subgraphs.