As H. dromedarii asiaticum: Schulze and Schlottke 1930. Olenev 1929A,1931A,C,1934. Galuzo 1934. Pomerantzev 1950. Some of these may apply to H. excavatum, this is especially likely in the case of Galuzo 1934. Feldman Muhsam 1954 does not accept Delpy's synonymy of this form under H. dromedarii but does not provide reasons or suggest a substitute.

As H. aegyptium dromedarii:

Yakimov 1917,1922.

As "H. tunesiacum amurense Schulze": described and illus trated by Kratz 1940. Delpy 1949B attributed "H. amurense Olenev, 1931C" to H. excavatum.

As H. pavlovskyi: Olenev 1931C. Galuzo 1935. As H. yakimovi: Olenev 1931A,C. Galuzo 1935. Pospelova Shtrom 1932.

MIDDLE EAST: AFGHANISTAN (Hoogstraal, ms.). INDIA and PAKISTAN ZAS H. asiaticum citripes: Schulze (1934X). As H. d. citripes: Kratz (1940) According to Delpy (19493) these are synonyms of H. dromedarii. Feldman Muhsam (1954) states, without further explanation, that they are not. Records of H. dromedarii by Sharif (1928) and Sen (1938) are questionable.7

FAR EAST: TIBET (and MONGOLIA): As H. kozlovi: Olenev 1931B. Kratz 1940. As H. asiaticum kozlovi: Pomerantzev 1950. INDOCHINA: The H. d. indosinensis of Toumanoff (1944) refers to H. marginatum.

IMPORTED SPECIMENS: ARGENTINA (Found on camels from Dakar: Lahille 1914).

NOTE: Portugese material under this name (da Silva Leitao 1945) is assumed (HH) to be misidentified.

HOSTS

Until recently, only the hosts of adult H. dromedarii were known. These are chiefly camels, but also include cattle and

horses and, to some extent, sheep, goats, and dogs. Man is un commonly attacked by adults, but more frequently by larvae and nymphs. H. dromedarii is so intimately associated with camels that it does not occur outside the normal range of these animals. However in parts of Anatolia where camels are now considerably less numerous than heretofore, large numbers of adults have been found on cattle and horses, fewer on sheep and goats (Hoogstraal, ms.).

In nature, remote from large concentrations of domestic animals, larvae and nymphs feed on small burrowing mammals and hares, rarely on lizards. Adults venture forth in search of larger hosts. Nymphs appear to be more versatile, depending on local situations, and may infest camels, cattle, and horses in large numbers. Factors inducing the selection of hosts by nymphs are in need of study.

In the laboratory, Delpy and Gouchey (1937) fed larvae on hares and calves but this stage rarely engorged on camels or sheep. The same was true for nymphs. Adults attached rapidly to camels and cattle, rarely to sheep. It was often difficult to rear on a calf the F1 generation of a female collected on a camel. Further review of Delpy and Gouchey's report is presented in BIOLOGY below.

In Yemen, Southwestern Arabia, numerous larvae and nymphs have been collected from the following hosts (Hoogstraal, ms.):

Lepus arabicus arabicus Ehrenberg

Lepus arabicus subsp.

Rattus rattus rattus Linnaeus (rare)

Gerbillus cheesmani maritimus Sanborn and Hoogstraal

In Egypt, including Sinai, nymphs have been taken from hedgehogs, hares, rodents, and lizards (identifications based on adults reared from nymphs) (Hoogstraal, ms.).

Hemi echinus auritus aegyptius Fischer (common on
Mediterranean littoral)

Paraechinus aethiopicus dorsalis Anderson and De Winton
(few hosts examined)

Lepus capensis sinaiticus Ehrenberg (few hosts examined)
Lepus capensis aegyptius Desmarest (common)

Gerbillus (Lipodillus) quadrimaculatus Lataste (rare)
Gerbillus g. gerbillus Olivier (fairly common)
Gerbillus p. pyramidum Geoffroy (common)

Meriones c. crassus Sundevall (common, also in burrows)
Meriones S. shawi Duvernoy (common, also in burrows)
Psammomys o. obesus Cretzschmar (common, also in burrows)
Jaculus j jaculus Linnaeus (rare)

Acanthodactylus boskianus Daud. (Lizard) (uncommon)

According to Pomerantzev (1934) hosts of the immature stages in Armenia include reptiles and wild birds. The fatty sub cutaneous layers of ground squirrels, Citellus sp., used as laboratory hosts (Pospelova Shtrom 1932), may hinder the attach ment and feeding of larval H. dromedarii (= H. yakimowi).

In Russia (Pomerantzev 1950), adult hosts are camels, horses, and sheep while nymphs feed in large numbers on cattle and camels. Hosts of adults of the synonymous H. asiaticum are camels, cattle, horses, and sheep; rarely donkeys, goats, domestic and wild pigs, hares and hedgehogs; sometimes man. Nymphs of this latter form occur on hedgehogs, in burrows of large "peschanki" and gophers, while larvae are often on hedgehogs. Both immature stages are found (?together) on hares, gophers, jerbo as, "peschanki", cats and dogs, and single nymphs are found on cattle and sheep (Bogoroditsky and Bernadskaia 1938).

BIOLOGY

Life Cycle

The question of the normal number of hosts of H. dromedarii is moot. Delpy and Gouchey (1937) consider it as a three host tick that may utilize only two hosts under unfavorable conditions; i.e. great heat, when larvae molt quickly and reattach as nymphs nearby on the same host in order to avoid desiccation. It would appear that normally, on burrowing mammals, this need would not arise since the hosts venture from their relatively cool tunnels only after the sun goes down (deserts are usually cool at night).

Alfeev (1951) reared H. dromedarii as a single host tick on rabbits and noted that adults move to new positions shortly after molting and remain unattached to the host for a day or two afterwards.

Field observations suggest that this is normally a two host tick, the change in hosts usually occurring after the nymphal adult molt, infrequently after the larval nymphal molt (Hoogstraal, ms.). In Russia the former type appears most common (Pomerantzev 1950).

Experimentally, Pospelova Shtrom (1932) bred H. dromedarii (= H. yakimowi) on one, two, or three hosts. For the single host life cycle, she employed the hedgehog. The highly artificial conditions and exceptional hosts utilized in this experiment pre clude additional deductions from the results.

During the warm season in Iran, the briefest life cycle ob served by Delpy and Gouchey (1937) was 93 days: During cold weather, 280 or more days were necessary. Two generations a year may occur in nature. Variations in life cycle length are due to external or climatic factors affecting oviposition, hatching, and premolting periods; feeding times are similar at all seasons. These findings are diametrically opposed to those of Pospelova Shtrom (loc. cit.), who concluded, after rearing two generations under different temperature and humidity conditions, that varia tions in the length of different stages depends more on host bodytemperature than on atmospheric differences. The Delpy-Gouchey conclusions are more in line with usual concepts concerning factors affecting tick life cycles. (See page 704)

In Egypt, some slight seasonal variation in incidence of adults on camels is noticed (Hoogstraal, ms.). Normal life cycle activity appears to continue the year around, except that it is slower during the winter. For instance, during the summer, nymphs molt to adults from seventeen to 26 days after dropping from the host while in winter this period is extended to from 27 to 48 days.

Feeding time for each stage, according to Delpy and Gouchey, is as follows:

These authors reported individual females laying from 2000 to 8000 eggs, but Pomerantzev (1950, for the synonymous H. asiaticum) notes as many as 14000 eggs.

Males mate with unengorged or with feeding females while on the host. In the absence of males, females either detach prematurely from the host or remain fixed for an exceptionally long time as long as two months.

In the Kazalinski district of Russia (Pomerantzev 1950), adults parasitize domestic animals from April to the end of October, but are most common from May through August while larvae and nymphs attack hedgehogs in July and August. Fe males that become engorged late in autumn undergo a winter diapause and do not oviposit till spring.

Ecology

Delpy and Gouchey (1937) found H. dromedarii to be very tolerant of low humidity and extremes in temperature (0°C. to 37°C.). Unfed larvae and especially unfed nymphs avoid dry atmosphere more than engorged stages and adults.

H. dromedarii is probably the most completely desert-adapted of all ixodid ticks. In remote Siwa Oasis of Egypt, it, together with R. sanguineus, is the only common ixodid tick. Italian and French observers elsewhere in North Africa and Soviet workers in Russia have made similar observations. The camel hyalomma ap pears to be equally at home in all desert situations where ani mals occur, as well as in semidesert and steppe areas. In Yemen and Eritrea, it is also common in mountainous areas to 7000 feet altitude wherever there are people and camels (Hoogstraal, ms.).

When traveling over remote parts of the African and Arabian deserts engorged females have been observed desperately crawling