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little if any wandering. If a female is placed near a male, considerable excitation is caused. A male may copulate with several females, but females apparently accept only a single male. Copulation may be very swift or may apparently extend over several days. Females do not move from their feeding site until they drop from the host.
In Algeria, adults are rarely seen in winter but begin to appear in March and continue till October, maximum densities being reached in April, May, and June (Algerian seasons are comparable to those of southern United States). Nymphs are found mostly during the summer. With slight variation, this seasonal picture is typical for H. marginatum wherever it ocCui'S
In the Crimean forest (Melnikova 1953) adults are found during the summer, March to September, but rare individuals (?mostly males) may be seen at any time of the year. Larvae and nymphs infest hares from the end of June to the first half of September. Nymphs are most common on hares in the latter part of August; for example, a hare on 2 August yielded 100 nymphs while another on 17 £ yielded 390 nymphs. In this forest reserve, H. marginatum (= H. p. plumbeum) occurs in all ecological #: # pure stands of conifers, it is, however, comparatively rare. The most
favorable habitats appear to be valleys with small open fields between the mountains.
In Transcaucasia, this species occurs equally in both highland and forest zones and in desert and steppe formations and is found in every type of landscape in that area (Pomerantzev, Matikashvily, and Lototsky 1940). In Armenia, it occurs in the Artemesia semidesert of the Arax valley (Pomerantzev 1934) and at altitudes of 6500 feet and over (Lototsky and Popov 1934).
On the Crimean steppes, adults are most common in July (May and June according to Kurchatov 1940A). There, the greatest
density of this tick is around haystacks and in fallow fields where their immature stage host, the European hare, hides and feeds. Engorged nymphs drop from hares in autumn and overwinter in that stage. They molt in the spring, and adults attack cattle, sheep, horses, and man. The devastation of the Crimea during the war, followed by a great increase in hares and their ticks, was significant epidemiologically in the outbreak of highly virulent, often fatal hemorrhagic fever at that time.
Gynandromorphs of H. marginatum have been described and illustrated by Pervomaisky - e same author (1949) was unable to secure a complete Fl generation from parthenogenetic females of this species.
Schulze (1932C) illustrated certain of the cuticular sense organs of two of his "subspecies" of this species, also "gynotropes", males with more dense punctations on the scutum conforming to those of the female scutum in location and distribution. This species has been utilized in a study of sensory physiology (Totze 1933).
When large numbers of ticks (as H. plumbeum) feed on a restricted area of the host, the females and sometimes also males fail to engorge completely and may die; their development is far from normal. When different species are competing for the same feeding area, this additional competitive factor often hinders their normal development (Pavlovsky, Pervomaisky, and Chagin 1954).
MAN: H. marginatum is considered to be the chief vector of the virus of c:# fever. The extensive geographic range of this tick and its large population in many areas where it occurs - factors that suggest a high potential as a medically important species - appear to be generally unappreciated outside of Crimea. This species is not involved in the transmission of Omsk hemorrhagic fever, since it does not occur in that area, So far as is presently known.
Specimens naturally infected with Q fever (Coxiella burnetii) have been found; this species is a vector of the organism transmits it through all stages including the egg.
Brucellosis or undulent fever organisms, Brucella melitensis, survive some time in this tick, which is said by some Sovie workers to be a carrier and transmitter of this pathogen. Some Russian studies of ticks as animals sustaining natural foci of tularemia have negated the importance of H. marginatum (as H. plumbeum) in this regard, although other workers have reported
the finding of naturally infected specimens.
CATTLE: Theileriasis (Theileria spp.).
HORSES: Theileriasis (Theileria equi) and piroplasmosis (Piroplasma caballi). Transovarial transmission of the latter # to the seventh generation has been demonstrated.
GUINEAPIGS: Rickettsiae pathogenic to these animals and transovarially transmitted to the F3 generation of H. marginatum have been reported.
Males: The combination of characters for recognizing typical males is: (1) the center of the subanal shields is directly posterior of the central axis of the adanal shields (which are large and broad); (2) the lateral grooves are long, reaching approximately to the eyes, but they are frequently somewhat obscured by dense punctations or by lack of discreteness, especially anteriorly; (3) the scutal punctations are dense and large in the distal and scapular fields, but variable elsewhere, being usually smaller and more shallow and less dense centrally; (4) the posteromedian groove reaches the scutal midlength, it is narrow anteriorly and wider posteriorly; the paramedian grooves are about half as long as the posteromedian groove and taper from a pointed apex to wide in the festoon area; a narrow heavily punctate ridge lies between the paramedian grooves and the lateral grooves.
The scutum is usually comparatively narrowly elongate, measuring approximately 4.0 mm. long and 2.5 mm. wide. Its color is typically dark brown to black, but reddish specimens also occur; the legs may be entirely reddish or reddish centrally on each segment with paler anterior and posterior bands (see next paragraph). The scutal punctations may be dense enough to suggest H. rufipes, but those in the center are shallower and smaller than elsewhere, while in H. rufipes they are deep and quite uniform in size and depth. The parma may appear to be merely a median festoon and is the same color as the rest of the scutum. The subanal and adanal shields have rounded contours; the adanal shields are quite large.
Heavily punctate males, as seen among series from Libya, Algeria, Egypt, Romania, and elsewhere may suggest H. turanicum (page 531). The legs of H. # however, lack the con
spicuous enamelling characteristic of those of H. turanicum.
Females: The genital apron is a large, robust widely transverse oval or triangle with a strongly bulging profile; it is most characteristic. The scutal punctation consists of numerous small, shallow, distant punctations over the entire surface (they may be almost medium size and slightly deeper and closer), and a few larger and deeper punctations scattered among them chiefly on the anterior half of the scutum. The basic punctation in some specimens is so shallow as to give scutum a rather smooth appearance, especially posteriorly. The central field between the cervical grooves is usually lighter (more reddish) than the dark lateral fields. The scutum appears to be exceptionally wide, its length-width ratio being about equal or shorter than wide.
Females of H. marginatum and H. turanicum are quite similar but the bright enamelling of the leg segments of H. turanicum distinguishes them. In most specimens of H. turanicum the genital apron is not so widely triangular and the scutal punctations are more numerous and discrete than in H. turanicum.
The larva and nymph of H. marginatum have been described and illustrated by Bernadskaia (1939C) and Feldman-Muhsam (1948).