Passing along the Crocodile river, where a drought set in and drove the game to the neighbourhood of the river, Selous managed to kill a few good specimens of hartebeest and wildebeest which he preserved. Diamond proved a splendid shooting horse, but another mount, Nelson, which was at first intractable, eventually became a valuable animal, as he successfully survived the prevalent sickness. This horse, though somewhat slow, did Selous yeoman service for several years, and he eventually sold it to Lewanika, chief of the Barotsi, in 1888. At this time Selous hunted industriously to make a good collection of butterflies, and after many years he did make a very complete collection, which he presented to the Cape Town Museum. The curator of this museum was the late Mr. Trimen--a man for whom Selous had a great respect--who was ever delighted to receive any novelties, and many were the new species discovered by these two active entomologists. Selous, in fact, had all his life collected butterflies, and did so almost to the day of his death in German East Africa, for it was nothing to him to chase agile insects in the heat of the day, when other men only thought of rest and refreshment. The capture of some new species was to him always a great event, and though others, less interested than himself, wondered at his taking so much trouble about a wretched butterfly, he had all the absorbing pleasure of finding some new thing, the ambition of all true naturalists. One day, whilst butterfly hunting, he found an ox bogged in the mud of the river. The poor beast had been badly bitten by crocodiles, which are perhaps more numerous in the Limpopo than in any river in South Africa, except perhaps the Botletlie. Numerous goats and calves belonging to natives were annually destroyed there, whilst in 1876 a Boer hunter named Berns Niemand met his death from these reptiles whilst crossing the river. At the Notwani river, on March 5th, Selous decided to visit Khama and ask his permission to travel along the Limpopo and up the Mahalapsi river to Matabeleland. He rode by night, and "off-saddled" to give his horse a rest and feed for half an hour.