confusus is scattered throughout desert and desert edge retreats, all arid, such as antiquities structures, caves, and hillside crannies.

Records from northern Sudan and from the Protectorates of South Africa indicate a more or less similar tolerance of aridity, but those from various regions of South Africa, Torit, and the crater of Mt. Menengai in Kenya indicate also that certain popu lations exist in markedly humid environments where they tolerate lower temperatures and higher relative humidity than they do in Egypt.

DISEASE RELATIONS

BATS: A small number of specimens thus far studied in NAMRU-3 laboratories have been negative for blood protozoa, spirochetes, viruses and rickettsiae, and Shigella organisms.

REMARKS

Further studies on the habits and ecology of this species are presently under way and will be reported when completed. For a definition of the subgenus Chiropterargas and for criteria to dis tinguish this species from A. boueti, see page 95.

IDENTIFICATION

A. confusus adults have an extremely wide body outline, and, in common with A. boueti, are characterized by the absence of a sutural line dividing dorsal and ventral surfaces, and by the pres ence of a conspicuous hood over the mouthparts. In A. confusus the dorsal integumental protuberances are fine, shiny-tipped, tapering points which on the lateral margin are more closely spaced and more regular. The posterior discs are arranged radially; the legs are shorter than the body length; and the hypostome has only a single pair of denticle files. The tarsi have no dorsal protu berances. A pair of grooved organs of unknown function is present just posterior of the anus on the ventral surface.

Except when greatly engorged, the peripheral flange of the body remains partly unfilled. In partially engorged individuals this flange is flat, and in dry specimens it may be turned up like a rim. The body color is reddish yellow with a central, darker area of varying extent.

Males measure from 5.9 mm. to 6.4 mm. long, and from 7.4 mm. to 7.8 mm. wide (average 6.1 mm. long and 7.5 mm. wide). The genital aperture forms a wide arc. Females are larger, and measure up to 8.0 mm. long and 9.5 mm. wide. The female genital aperture is a transverse groove with thick, rugose lips.

The nymph and larva have been described by Hoogstraal (1955B). The larva and first instar nymph are quite similar to those of A. boueti but the successive instars of each resemble the associated adults.

Figures 37 and 38, d, dorsal and ventral views

ARGAS (CARIOS) VESPERTILIONIS (Latreille, 1802).

Northern:

DISTRIBUTION IN THE SUDAN

One larva from an undetermined species of bat at Dongola, 12 April 1917, Bedford legit; Sudan Government collections.

Khartoum: Several larvae from an undetermined species of bat (s?) at Khartoum, 20 September 1914, R. Cottam legit; in Sudan Government collections, one retained in Hoogstraal collection.

DISTRIBUTION

The Argas vespertilionis group, consisting of A. vespertilionis (Latreille, 1802) in Europe and Africa, A. pusillus Kohls, 1950, on Palwan Island in the Philippines, and of numerous closely related forms of yet uncertain species status, ranges throughout the continents and island groups of the world, except in the Americas. It is possible that certain African populations presently identified as A. vespertilionis will prove to be separate, closely related species. A fuller study of this group is under way.

African Records Only

Eventually, the round bat argas most likely will be found in many more territories of Africa.

*Field identification of host; specimen not seen by a specialist in bat taxonomy.

NORTH AFRICA: EGYPT (As A. fischeri: Audouin 1826, Savigny 1827, and Lavoipierre and Riek 1955. Hoogstraal 1952A). TUNISIA (Colas Belcour 1933B).

WEST AFRICA: FRENCH WEST AFRICA: Although reported as A. vespertilionis by Marchoux and Couvy (1912A,B,1913A,B), there is some likelihood that some or all of these specimens may have been those subsequently used as the types of A. boueti. Rousselot (1953B). GOLD COAST (Simpson 1914).

CENTRAL AFRICA: BELGIAN CONGO (Schoenaers 1951A).

EAST AFRICA: SUDAN (King 1911,1926; in part. Hoogstraal 1954B).

KENYA (HH collecting in crater of Mt. Menengai).

SOUTHERN AFRICA: ANGOLA (Larvae from Dundo, Lunda, north eastern Angola, CNHM). MOZAMBIQUE ("Brumpt's Precis"). SOUTHERN RHODESIA (Jack 1932. Bedford 1934).

UNION OF SOUTH AFRICA: South African adults described and illustrated by Nuttall et al (1908) as A. vespertilionis represent A. confusus. Howard (1908, Dönitz (1910B), Bedford (1932B,1934), also confused these two species as probably also did Cooley (1934); cf. Hoogstraal (1955B, p. 586) for details. Dr. G. Theiler has sent a female and nymph of A. vespertilionis from Pretoria and Grahamstown. These were among larger numbers of A. confusus and A. boueti. No specimens of A. vespertilionis were included with material of A. confusus and A. boueti from collections of the South African Institute for Medical Research, recently sent for identification by Dr. F. Zumpt. These observations lead one to suspect that A. vespertilionis may be less common in South Africa than A. confusus.

OTHER AREAS: Available material referable to this group is from England, Netherlands, Sweden, Spain, Germany, Korea, China, Philippines, and Ceylon. The group is also known to occur in southern India, Cambodia, Australia, France, Italy, and Russia. Differences between African and European specimens and those from Australia and Asian areas are very slight indeed.