light infantry

plural light infantries

1. countableuncountableGround combat soldiers who are not mechanized, and whose role is to harass the enemy in front of the main body of infantry.
2. archaiccountableslanguncountableBedbugs or fleas.

   The affair began by a skirmishing of the fleas, who acted as cavalry; then came the main body of lice, followed by the light infantry of bedbugs, to the number of forty thousand.

   1906, Samuel Gridley Howe, Laura Elizabeth Howe Richards, Letters and Journals of Samuel Gridley Howe, page 109

   2 more examples

   Our bed was a waterproof sheet on the bare stone-floors, and as the convent swarmed with fleas of all sizes, from the heavy dragoon down to the light infantry, there was no fear of a sentry sleeping on his post.

   1887, Andrew A. Anderson, Twenty-five Years in a Waggon in the Gold Regions of Africa, page 59

   What they dealt with in giving nursing care was in addition to the constant influx of lice, the “light infantry” of fleas, frequent harassment by droves of huge rats, earthquakes, the fickle weather of the Russian winter, […]

   2006, Callista Roy, Dorothy A. Jones, Nursing Knowledge Development and Clinical Practice, page 46