Nearly 800 fumigations, in which 20,000 insects of about 15 different species were fumigated, were made. The following were fumigated in small glass cylinders, both ends of which were covered by cloth held in place by rubber bands: Ants (Tetramorium caespitum Fab., Monomorium minimum Buckley, Monomorium phamonis L., Lasius niger L., var. americanus Emery); bedbugs (Cimex lectularius L.); bedbug eggs; potato beetles (Leptinotarsa decemlineata Say and Epitrix cucumeris Harris); flat grain beetles (Laemophlaeus minutus Oliv.); sawtooth grain beetles (Silvanus surinamensis L.); grain borers (RMzopertha dominica Fab.); flies (PJiormia regina Meig., Calliphora vomitoria L., Musca domestica L., Stomoxys calcitrans L., CTirysomyia macellaria Fab., and Lucilia sericata Meig.); roaches (BlatteUa germanica L.); roach egg pods; flour weevils (Tribolium ferrugineum Fab.); and rice weevils (Calandra oryzaeh.). The following insects were fumigated on their hosts: Aphids (Myzus persicae Sulz.); white fly (Aleyrodes vaporariorum Westw.); Phyllostachys bamboo mite (Tarsonemus sp.); and red spider (Tetranychus bimaculatus Harvey).Checks were kept on all insects, and no results are given for insects whose check showed any dead. The observations were begun when the insects were removed from the fumigatorium. and continued up to the time the percentage of dead became constant for any two successive days.The checks and treated insects were kept under the same conditions until the final observation was made. All of the insects, except ants, aphids, red spiders, and white flies, were held in the container in which they were fumigated. The bedbug eggs were fumigated and kept in chiffon-covered pill boxes, in which the eggs had been deposited. After fumigation the ants were removed to tumblers containing moist sand. Having been fumigated on their hosts, aphids, red spiders, and white flies were transferred to glass tumblers containing moist sand and fresh uninfested material.Roach egg pods were handled in the same manner as ants.The following fungi were treated: Fusarium, Ascochyta, Penicillium, Colletotrichum, and Sclerotium. In some cases these fungi were placed on a petri dish in a drop; in others, sterilized seeds were inoculated by a spore suspension, and exposed in the same manner as the insects.