| 1 |  | Body elliptical (sides curved) | 2. |
| Body oblong (sides straight), ending anteriorly in a point | 7. | ||
| 2 | | Body transversely oval | vespertilionis. |
| Body elongate oval | 3. | ||
| 3 | | Margin of body striated | 4. |
| Margin of body formed by quadrangular areolæ | PERSICUS. | ||
| 4 |  | Body flat, integument plainly wrinkled | 5. |
| Body tumid, elongate; integument finely wrinkled; coxæ of fourth pair of legs near anterior third of body | hermanii. | ||
| 5 | | Body oval, narrowed anteriorly | REFLEXUS. |
| Body elliptical, blunt, hardly narrowed anteriorly | 6. | ||
| 6 | | Body twice as long as broad | cucumerinus. |
| Body hardly longer than broad | transgariepinus. | ||
| 7 |  | Dorsal integument with large polygonal depressions; tarsi appearing bifid | BRUMPTII. |
| Dorsal integument almost smooth; tarsi not appearing bifid | æqualis. |
The Argantinæ are distinguished from the Ixodinæ by the head, which in the former is situated on the inferior aspect of the cephalothorax, while in the Ixodinæ it projects freely; also by the very short proboscis, the small club-like palpi, the lack of suckers on the legs, as well as by the scutellum, which covers the entire back and is bent up round the borders. Two genera are distinguished: Argas, Latreille, 1796 (Rhynchoprion, Hermann, 1804), and Ornithodorus, Koch, 1844. The species live on mammals, but more especially on birds.
Genus. Argas, Latreille.
Argas reflexus, Fabricius, 1794.
Syn.: Acarus reflexus, Fabricius, 1794; A. marginatus, Fabricius, 1794; Rhynchoprion columbæ, Hermann, 1804.
Fig. 361.—Argas reflexus: from the dorsal surface, the intestine showing through the integuments. (After Pagenstecher.)
The European marginated tick, Argas reflexus (length of male 4 mm., breadth 3 mm., length of female 6 to 8 mm., breadth 4 mm.), is of a yellowish colour and has yellowish-white legs. The ingested blood shows red or brown through the intestine, which is provided with blind sacs. It lives in dovecots. It remains hidden during the day and at night crawls on to the sleeping pigeons to suck their blood. It has been observed in France, England, Italy, Germany, and Russia. Persons sleeping near infected dovecots, or in apartments formed from pigeon-lofts, are also attacked, even when the room in question has not been used for sheltering pigeons for years, as “marginated ticks” can live in a fasting condition for a very long time. The bite sometimes gives rise to serious symptoms, such as general erythema and sudden œdema.