Which poetic device is illustrated by the line, “. . all night long, by a fire-fly lamp”?

delfino 2: diez in the desert analysis: the story, delfino 2: diez in the desert was really about not giving up! that is basically the theme of the story, and also being more prepared. the plot of the story was about diez, the main character, traveling through the harsh desert with other immigrants. also, that keeping the group alive and getting them to their final destination. the setting of the story took place in mexico in the harsh desert.