Sand flies are small, winged insects that belong to the family Psychodidae. They are often found in sandy or marshy areas, especially in tropical and subtropical regions. These tiny flies are known for their painful bites, which can cause itching and irritation. Sand flies are most active during dusk and dawn, making them a nuisance for outdoor activities. These insects are also important because they can transmit diseases, such as leishmaniasis, a serious illness caused by parasites. Protecting yourself from sand flies involves using insect repellent and wearing long sleeves and pants when in areas where they are common.