Hematophagous arthropods exhibit essentially two basic feeding styles, solenophagy (vessel feeding) and telmophagy (pool feeding). Solenophagous arthropods typically feed within minutes, causing minimal tissue destruction, but intense allergic reactions of immunological nature may follow. Tehnophagous arthropods usually have a longer feeding period ranging from minutes to days. As a result, tremendous tissue destruction may occur, followed by allergic reactions that may persist for months or years. Solenophagous arthropods discussed in this paper are Triatoma protracta (Uhler) and Xcnopsylla cheopis (Rothschild). Feeding by these arthropods induces blood and tissue basophilia in guinea pig hosts upon challenge. Triatoma feeding induced a strong eosinophilia to accompany the basophilia. The possibility of these host responses interfering with arthropod biologs is discussed. The response of guinea pigs to tehnophagous arthropods is examined using the following examples: Amblyomiim americanum (L.), Rhipicephalus appendictdatus (Neumann), Ornithodorus tartakovskyi Olenev, and Ltitzomyia longipalpis (Lutz & Neiva). Ixodid ticks all feed for days, causing considerable tissue damage associated with exacerbated blood and tissue eosinophil and basophil responses. The massive accumulation of these cell types at tick feeding sites are believed to play an important role in the phenomenon of host acquired resistance. The sand fly feeds for only minutes but induces considerable blood and tissue response. The tsetse fly, Clossina morsitans Westwood, exhibits a feeding style intermediate between solenophagy and telmophagy and induces very strong blood and tissue basophilia and eosinophilia similar to ticks. The presence of host acquired resistance to the tsetse fly is discussed.