The Orb-Weaver Genus Witica (Araneae: Araneidae)

Two species of neotropical orb-weavers, "Edricus" crassicauda and Witica talis, have each been known from a single sex, the first from females only, the second from males. The male of Edricus spinigerus, suspected by F.P.-Cambridge (1904) to belong with the female Epeira crassicauda, has never been collected with it, although Cambridge’s suspicion was the reason for placing the female E. crassicauda in the genus Edricus. While parthenogenesis could account for absence of males in E. crassicauda, the absence of females in Witica was more perplexing. The large females of Epeira crassicauda have a tail with a constriction (Fig. 1), the minute males of Witica talis (Fig. 5) have a round, subspherical abdomen bearing a glossy plate. The two placed in different subfamilies did not appear to be likely mates. Surveying our collections, I found males of Witica to have been collected in Cuba, Puerto Rico, Central and northern South America, roughly the same distribution as the female specimens named "Edricus" crassicauda. Both are fairly common on Barro Colorado Island in Gatun Lake of Panama, from which large collections are available. Unexpected evidence for existence of males in E. crassicauda turned up: a male palpal part was found in the microscope slide preparation of the seminal receptacles. When expanding the palpus of Witica talis, I noticed that the structure first considered to be the conductor, and which is sometimes missing from specimens, is actually an appendage of the embolus. Further, its structure is remarkable, including a hand with many fine teeth, presumably functioning as a hold-fast inside the female genital duct (Fig. 11). Subsequently,