Ocular injuries by vesicatory insects appear exceptional and the authors have not found any reports in the literature. Cantharidine, with toxicity comparable to that of mustard gas, can be present in many species of coleoptera. It results in progressive corneal necrosis ending in ocular perforation in 30 days. The necrotic process persists with long duration because this material is not broken down. It provokes deep ocular injuries (cristalline lens). The inflammatory reaction is severe with acute refractory hypertension. There exists no antidote, only prevention is useful. Emergency penetrating keratoplasty with anterior chamber lavage should help eliminate the toxin. In daily practice, the authors observe similar but less serious injuries; they think that they could be due to dust rich in vesicatory insect debris or their secretions.