When economic entomology concerns itself in the line of biological control further than the introduction of foreign parasites to offset the inroads of introduced pests and turns for help to our indigenous hordes of balancing agents, as it must do some day, college professors may well direct their students to Papaipema biologies. Here an easy exposition of what holds a large genus to innocuous bounds is amply portrayed and, as hosts to such a retinue which goes still further afield, proclaims them in fact helpful species of our biota.