_Ixodes ricinus_, the European castor bean tick (figs. 49, 50), is a species which has been often reported from this country but Banks (1908) has shown that, though it does occur, practically all of the records apply to _Ixodes scapularis_ or _Ixodes cookei_. In Europe, _Ixodes ricinus_ is very abundant and very commonly attacks man. At the point of penetration of the hypostome there is more or less inflammation but serious injury does not occur unless there have been introduced pathogenic bacteria or, unless the tick has been abruptly removed, leaving the capitulum in the wound. Under the latter circumstances, there may be an abscess formed about the foreign body and occasionally, serious results have followed. Under certain conditions the tick, in various stages, may penetrate under the skin and produce a tumor, within which it may survive for a considerable period of time. _Ixodes cookei_ is given by Banks as "common on mammals in the Eastern States as far west as the Rockies." It is said to affect man severely. _Amblyomma americanum_, (fig. 158c), the "lone star tick," is widely distributed in the United States. Its common name is derived from the single silvery spot on the scutum of the female. Hunter and Hooker regard this species as, next to _Boophilus annulatus_, the most important tick in the United States. Though more common on cattle, it appears to attack mammals generally, and "in portions of Louisiana and Texas it becomes a pest of considerable importance to moss gatherers and other persons who spend much time in the forests." _Amblyomma cajennense_, noted as a pest of man in central and tropical America, is reported from various places in the south and southwestern United States. _Dermacentor variabilis_ is a common dog tick of the eastern United States. It frequently attacks man, but the direct effects of its bite are negligible. The "Rocky Mountain spotted fever tick" (_Dermacentor andersoni_ according to Stiles, _D. venustus_ according to Banks) is, from the viewpoint of its effects on man, the most important of the ticks of the United States. This is because, as has been clearly established, it transmits the so-called "spotted fever" of man in our northwestern states. This phase of the subject will be discussed later and it need merely be mentioned here, that this species has been reported as causing painful injuries by its bites. Dr. Stiles states that he has seen cases of rather severe lymphangitis and various sores and swellings developing from this cause. In one case, of an individual bitten near the elbow, the arm became very much swollen and the patient was confined in bed for several days. The so-called tick paralysis produced by this species is discussed in a preceding chapter. There are many other records of various species of ticks attacking man, but the above-mentioned will serve as typical and it is not necessary to enter into greater detail.