Harvestman. Coloured scanning electron micrograph (SEM) of a harvestman (order Opiliones). Harvestman differ from spiders by having only one pair of eyes on a centrally positioned ocularium, they do not have venom glands or hollow fangs and are devoid of silk glands. The pedipalps are generally less complicated than spiders and are believed to be tactile sensory organs. Unlike spiders, there are small differences between the sexes which are shown on the pedipalps. A harvestman catches its insect prey by using hooks on the ends of its legs. These arachnids defend themselves by secreting a foul-smelling fluid. If they are caught, they are able to shed a leg to escape. Magnification: x20 when printed at 10 centimetres wide.