The genusLonomiaWalker, 1855 (Lepidoptera: Saturniidae) is of particular interest to the medical community, since the scoli of these caterpillars harbor a venom that induces hemorrhaging in humans. In Colombia, deadly encounters withLonomia achelous(Cramer, 1777), have been reported since 2000. There is little information on the main biological and ecological aspects of this genus to help better understand and develop prevention strategies. This study aimed to describe morphological and biological aspects (especially of immature stages) of four recently reported species ofLonomiain Colombia that pose a risk to humans. We collected caterpillars and adults from five localities and reared them under laboratory conditions. Specimens were identified using DNA barcoding and dissection of adult male genitalia. We provided the first description, to our knowledge, of part of the life cycles ofLonomia casanarensisBrechlin, 2017 andLonomia orientoandensisBrechlin & Meister, 2011 and the complete life cycles ofLonomia columbianaLemaire, 1972 andLonomia orientocordilleraBrechlin, Käch & Meister, 2013. We also present the first records of the parasitoids ofL.orientocordillera, andL.casanarensisand new host plants. This information will guide not only their morphological recognition and the identification of their parasitoids and hosts, but also will guide rearing methods of these and otherLonomiaspecies in new studies to prevent incidents with humans and create specific antivenoms.