Some Cuban Phoridæ Which Visit the Flowers of Aristolochia Elegans

During a stay at the Harvard Biological Station at Soledad, Cuba some time ago, Mr. Robert M. Grey, the Curator of the Botanical Garden showed me a beautiful group of Aristoloehia vines which are grown in one corner of the garden near his house. tie told me that they were regularly visited by small Diptera which he thought were Phoridm and since I have been interested in the members of this family for many years we searched in the few flowers present at that time in hopes of finding some flies. None were to be found, but Mr. Grey promised to send me some at the season when the Aristoloehias bloom in greater profusion. He did not forget his promise and I received recently a series of specimens which include two common species of West Indian Phoridm. These are Dohrniphora venusta Loew and Aphiochceta scalaris Loew, both present in apparently about equal numbers. It is of course well known that various small insects, particularly Diptera, enter the flowers of Aristolochia through t,he corolla tube which in some species is lined with reflexed hairs that prevent the escape of the visitors until the withering of stigmas and the opening of the anthers. Then the barricade of hairs withers likewise and the insects escape. As the flowers are protogynous, cross fertilization is affected by the first entrance of the insects if they come from another flower, and they later leave with pollen acquired toward the end of their imprisonment. Several observers have recorded the insect visitors of a number of species of Aristolochia (Spengel, Hildebrand, Delpino, Correns, Carry) nd find that, most of the insects are small Diptera of various kinds. Verrall (British Flies, vol. 1, p. 47) noted in England that Aristolochia clematitis is visi,ed most commonly by gall midges (Ionididm), although Mfiller and Delpino found