All biting insects identify their "victims" by the carbon dioxide flume that is given off when we breathe.
According to the Malaria Journal:
Female mosquitoes can carry a number of deadly infectious agents transmittable to humans via a bite. In 2017, approximately 700,000 deaths occurred as a result of mosquito bites from three divergent species of mosquitoes (Anopheles, Aedes and Culex) . Mosquitoes use their sense of smell to seek out and distinguish a vertebrate host for a blood meal. Disturbing a mosquito’s sense of smell can reduce host-seeking behaviours. The use of insect repellents, which can alter olfactory responses in mosquitoes, is one strategy of personal protection from host-seeking mosquitoes.
There are countless articles like these that have proven that plant based fragrances like those in Ole Time Woodsman Fly Dope can interfere with an insects ability to find you. This goes a long way in explaining how a formula developed over 100 years ago has been protecting those who spend time outdoors from all biting insects.
NOT finding you is much better than trying to protect you AFTER they have found you.