When swarms of locusts descended on the city of Fayoum early February 2, 1915, neither Cairo’s newly created Entomological Section in the Ministry of Agriculture, nor the learned members of its professional entomological society were prepared to handle the outbreak. The scientists swiftly realized that the studies of locusts swarms held in their libraries were not applicable to densely cultivated areas like Egypt. In lieu of a proper workforce, they required the villagers of the Egyptian countryside to observe, collect, and eradicate the insects. This paper relocates natural history--the study of insects in particular--from the colonial armchair to the rural Egyptian village to examine the fellahin as producers of entomological knowledge during the Great Locust Invasion of 1915. It argues that village omdas and fellahin held tacit knowledge regarding the destruction of locusts, as well as the insidious egg masses they produced, that informed the studies of “professional” entomologists working for the Egyptian Ministry of Agriculture and the newly founded entomological society in Cairo. What the fellahin had not learned from their experience with locusts during previous invasions in 1891 and 1904, they learned swiftly from circulars and informational documents that were distributed throughout the provinces to aid in containing the outbreak. Entire villages—men, women, and children—worked to observe, and collect locusts for dissection, while omdas and mamurs regularly telegraphed reports of the insects’ habits and movements back to Cairo. Armed with palm branches, fire, and paraffin tins, villagers took to the fields effectively eradicate the locusts that tormented their homes and crops.