Nymphal hosts: The Sudan hosts appear to be the only ones recorded for nymphs. These are Grant's gazelle, Roosevelt's hartebeest, rarely domestic cattle and dogs, and greater bustard. Nymphs were identified by Dr. G. Theiler. BIOLOGY A. lepidum is common in many of the semiarid regions of East Africa. It inhabits economically marginal areas and is not known to be a vector of animal or human disease pathogens. Therefore, not even the industrious veterinarians (in Africa they do most of the legwork on ticks for zoologists and for medical research ers) have investigated this tick's life history. It would, however, be surprising indeed to find that the life cycle were any other than the three-host type. J. B. Walker reports (correspondence) that larvae fed on a rabbit did not molt but that a few larvae in her laboratory have engorged on pigeons. In his interesting and important ecological survey of certain tick vectors of East and Central Africa, Wilson (1953) has noted the common occurrence of A. lepidum in the Karamoja area, the driest district of Uganda. Wilson includes this species in his discussion of the R. pravus - A. gemma association, reviewed herein on page (cf. also A. variegatum, page 681). These sections should be consulted to obtain a better impression of what is now known of the ecology of A. lepidum. Other species associated with it in Karamoja are R. e. evertsi, H. rufipes, and H. truncatum. For additional background, the following biological informa tion, as written in the manuscript before Wilson's (1953) paper became available, remains of value. Lewis (1939A) considered A. lepidum to be a desert species but, on the contrary, it appears to prefer more arid savannah country and, to some limited extent, semidesert regions. In Uganda it is most common in dry thorn country (Wilson 1950). Although Sudan cattle bound for the Cairo abattoir constantly carry the East African bont tick through the deserts and cultivated riparian areas of northern Sudan and Egypt, this parasite has not established itself in these places. I failed to find it in the French Somaliland semidesert. In the Sudan, A. lepidum is common in the central grasslands and in less rigorous semideserts but quickly disappears with the approach of extreme desert conditions. It also becomes more rare in mixed forest and in forested savannah country. Except for a few specimens mentioned in the paragraph below, fewer than ten specimens have been found in Sudanese areas with over fifty inches annual rainfall (see Bahr el Ghazal records above). The presence of this tick at Katire and Gilo, in the high rainfall area of the Imatong Mountains, is difficult to explain. These specimens were taken from cattle said to have been in the Imatongs for a long time", but most cattle, sent as adults, were soon slaughtered as required for lumbermill workers there. Although A. lepidum thrives in moderately low rainfall areas, it should be borne in mind that in the central grasslands, where this species is common, hosts often graze in marshy areas for months during the wet season, and that the dry season grazing area (toich) is also mucky for extended periods. Just where and when these animals acquire their infestations would be of interest. DISEASE RELATIONS In the Sudan, one frequently finds that large, ugly sores have developed on cattle and horses at the site of attachment of A. lepidum. REMARKS Features of haller's organ of A. lepidum were noted by Schulze (1941), who also (1950A) discussed the dentition of this species. IDENTIFICATION Male: The eyes are small, hemispherical, dark, and in a depression (i.e. orbited). Scutal ornamentation is as illustrated (Figure 68); note especially the pigmented spot at scutal midlength that is both within and outside of the lateral groove; also the six or eight partially pigmented festoons. Some large, deep punctations are scattered over the scutum; these are fewer than in A. pomposum but more numerous than in A. variegatum. The lateral groove is long. This is a medium size tick measuring approximately 5.0 mm. long and 4.0 mm. wide and is easily distinguished from all other species. Female: Easily identified in typical specimens but its critical characters are more variable than those of the male. Rather few females are extant in collections and when this species and A. variegatum are collected from the same herd a few questionable specimens may present themselves. Typically, the scutal contour is much more narrowed posteriorly than that of A. variegatum, but intermediate individuals do exist. Scutal punctations, usually coarse and crowded only in the lateral fields, sometimes spill over into the cen tral field; small punctations scattered over the scutum tend to become rather large in a few individuals. Pigmentation of most specimens consists of a narrowly elongate area in the central field posteriorly and a pair of small spots laterally, but this character is somewhat variable. Eyes, coloration, and relative size are like those of males. Figures 72 and 73, d, dorsal and ventral views AMBLYOMMA MARMOREUM GROUP Sudan (Juba) specimens from tortoise For note on scutal length width ratio of o, see IDENTIFICATION. PLATE XXVI - 224 Torit and Juba appear to be the only locality records avail able for the Sudan. A number of Varanus lizards and tortoises in Torit and Juba Districts and elsewhere in the Sudan have been examined but this tick was found only on the three reptiles listed above. Sudan Government collections also contain specimens from Atiambo, formerly in this Province but now a part of Uganda. *Sudan specimens referable to A. marmoreum fall into what is believed to be a group of closely related African species in need of careful study before definite names can be satisfactorily ap plied. References here are for any ticks for which the name A. marmoreum has been used. The term "A. marmoreum group", as here used, includes specimens that can be keyed to this name in the Robinson (1926) key, or that come close to it but do not equal related species such as A. nuttalli. The A. falso marmoreum of Tonelli Rondelli (1935) also falls into this group. The disposi tion of this group dictated by Schulze (1932A) is hopelessly un natural and practically useless. **The distribution of V. niloticus and related species is stated on page 283. K. b. belliana ranges as far west as Cameroons, where the subspecies nogueyi also occurs; the latter extends westward to Sierra Leone (Loveridge, correspondence). |