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organ with that of other Ixodes species is presented in table form by Arthur (1956B).

Remarks on morphology of this species are contained in papers by K. W. Neumann. These have not yet been seen and complete references are not available except for (1942) Z. Morph. bkol. Tiere, 38(2):358, 362. (Morphology of subcoxa of subspecies cumulatim£ctatus), and (1945) Zool. Jb. (Anat.), 69(2):286, fig. 8. Jakob #1's this species in his review of the relationship of tick genera from the standpoint of comparative morphology.

Both sexes are readily distinguished by their completely closed, usually circular anal grooves, an easily observed character in all specimens except some greatly engorged females in which the anal area is depressed and the associated grooves are difficult to discern. Only one other African species, Ixodes ugandanus Neumann, 1906 (with which Ixodes # Warburton, # from Uganda is quite possibly synonymous), is known to have closed anal grooves; these are not circular but characteristically oval and unite in a slight posterior elongation. I. ugandanus has not yet been found in the Sudan.

Schulze (1943A) indicated that circular anal grooves are characteristic of this species but that some specimens in which these grooves are expanded to a broad oval outline are merely atypical individuals of the same species. According to Schulze, the anal grooves of I. rasus may even be narrowed posteriorly.

Schulze (1943A) differentiated three subspecies of J. T8 SUS and one "related species" as follows:

I. rasus rasus: Short, broad palpi and hypostome; retrograde auriculae (lateral spurs of ventral basis capituli); pronounced single punctations on scutum. (From Cameroons).

I. rasus cumulatimpunctatus: Long, narrow palpi and hypostome; perpendicular auriculae; and small scutal punctations, some of which appear to be formed of a small group of smaller, contiguous punctations. (Tanganyika to Fernando Po).

I. rasus eidmanni' The same characters as given above for I. rasus resus, but "more strongly chitinized and darker", and

denticles of hypostome with a small apical "hook", proximity of sensory organs in the integument, and absence of a definite "peripheral zone" of the integument. (Rio Muni, or Spanish Guinea).

I. vanidicus: Similar to I. rasus but with anal grooves horseshoe-shaped or circular but not closed posteriorly. (Tanganyika to Cameroons).

IDENTIFICATION

Males are characterized by circular anal grooves (see REMARKS above), narrow marginal fold beside the scutum, fairly many to numerous fine scutal punctations, and short palpi with segments 2 and 3 of about equal length. This reddish brown species is about 2.8 mm. long and l.8 mm. wide and has a broadly rounded posterior margin. The tarsi are usually humped but in some specimens which otherwise conform to this description they are tapering.

Females also have closed anal grooves. Their scutal punctations are similar to those of males. The hypostome and palpi are long and narrow and the basis capituli ventrally has a large spur (auricula) arising from each lateral margin. The tarsi are either tapering or somewhat humped.

Note: As presently considered, any African Ixodes male or female with circular, closed anal grooves is I. rasus. Within the large amount of material seen in various collections there is considerable variation in most other characters, the significance of which await to be determined by Dr. Arthur.

Figures 226 and 227, d, dorsal and ventral views Figures 228 and 229, Q, dorsal and ventral views

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D.C.DES SCHILLINGSI Neumann, 190l.
(Figures 226 to 229)

THE COLOBUS RUSSET TICK

L N 9 d' EQUATORIA PROVINCE RECORD l Lotti Forest Colobus polykomos dodingae Apr

Lotti Forest is at 4500 feet elevation. This is the only record of this species from the Sudan. About a dozen monkeys of the same species examined in Lotti Forest and at other places at different altitudes in the same forest were free of ticks. An equal number of monkeys, Cercopithecus mitis stuhlmanni, from Lotti Forest were tickless, as were numerous specimens of other monkeys (Setzer 1956) examined elsewhere in the Sudan.

DISTRIBUTION

I. schillingsi, a parasite of East African Colobus monkeys, does not appear # range outside of wooded savannah and forested areas. It is the sole described African representative of a complex of species occurring in Asia, Madagascar, Australia, and Europe.

EAST AFRICA: SUDAN (Hoogstraal 1953E,1954B. Arthur, ms.).

KENYA (Nuttall 1916. Lumsden 1955. Arthur, ms. See HOSTS below). TANGANYIKA (Neumann 1901,1907C,1910B,1911. Nuttall and :* 1911. Morstatt 1913. Arthur, ms.). ZANZIBAR (Arthur, ITIS • J

SOUTHERN AFRICA: MOZAMBIQUE (Neumann 1919A, 1911. Nuttall and Warburton 1911." Santos Dias 1953B).

HOSTS

Man is parasitized by I. s. # according to a single record for a female tick of this species from Njoro, Kenya (Lumsden

1955). Aside from this, Colobus monkeys, also known as guereza or leaf-eating monkeys, are the only known hosts. As stated below, all other records from different mammals, including man and monkeys other than Colobus refer to undescribed Ixodes species or subspecies.

Colobus # caudatus (Neumann # ,1907C,1910B. :" and Warburton TCTDCIWRomos dodingae (Sudan record above). Colobus sp. (Nuttall #&####

Anderson (1924B) recorded Rattus rattus # as a host in Kenya. Specimens of this tick species collected by Anderson in Kenya, now in British Museum (Natural History) collections, are labelled as from Colobus monkeys and others bear no host data (Arthur, ms.). The rodent host is believed to be an error.

Lewis (1931C) listed this tick from a duiker, bushbuck, and domestic cattle in Kenya. These four collections, two from bushbucks and one each from the other hosts have been examined at British Museum (Natural History) and found to refer to an entirely different species. They were then referred to Dr. Arthur, who considers them to be an undescribed subspecies of Ixodes pilosus (Arthur, ms.). •

Rageau (1953B) reported ": £5 man and from another kind of monkey, Cercopithecus (= Lasiopyga) cephus cephus. These represent an undescri # species # to Erodes Sc ingsi

hur, ms.).

BIOLOGY

This species is a parasite of Colobus monkeys and uncommonly of man. It is said to prefer young hosts and attaches exclusively to the eye according to collecting notes furnished Neumann (1901). Females have been taken from around the eyes and ears and in the axillae of adult Colobus monkeys in Kenya and on the eyelid of a Colobus monkey in the Sudan.

The male has been found only in copula on the host (and once alone on a tree trunk) and its feeding ts are not known. Larvae, nymphs and both sexes of adults may occur on the same host (Arthur, ms.).

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