Pyemotes

Abstract: Detailed observations were made on nests of 3 species of Polistes wasps: P. annularis (L.), P. exclamans Viereck, and P. metricus Say. A summary of the records of the associated arthropods observed, together with those previously published, is given in tabular form. Twenty-three species of insects were known to be associated with Polistes nests in the United States; data on 18 additional insects and 1 mite species were gathered during this study. Symbionts and parasites reported for the first time are: Pyemotes sp., Lepinotus reticulatus Enderlein; Liposcelis bostrychophilus Badonnel; Ectopsocopsis cryptomeriae (Enderlein); Lachesilla sp.; the foreign grain beetle, Ahasverus advena (Waltl) ; the brown spider beetle, Ptinus clavipes Panzer; Trogoderma glabrum (Herbst) ; T. inclusum LeConte; the grape leaf skeletonizer, Harrisina americana (Guerin-Meneville) ; Tinea carnariella Clemens; Sarcophaga sp.; Megaselia aletiae (Comstock) ; Phaenolauthia sp.; Melittobia chalybii Ashmead; Perilampus chrysopae Crawford; Monodontomerus minor (Ratzeburg); Dibrachys sp.; and Dialictus zephyrus (Smith). Observations on these and 8 other species are given.

Abstract: Summary An acute outbreak of itchy papules among display artists (window–dressers) was traced to the presence of Pyemotes mites in imported dried ornamental wheat.

Abstract: Pyemotes mites, of which the grain itch mite is the most important for human medicine, are ectoparasites of many insect species. Human infestation occurs only accidentally and temporally. The source materials are most often grain, straw and plant-based foods. Bites produce an intensely itching urticarial wheal capped by pin-point vesicles, which often are destroyed by scratching. Pyemotes dermatitis favours the back, the abdomen and the flexor side of the forearms. The mites are barely visible to the naked eye and reside only briefly on humans and thus are not found by physicians during clinical examination. When itching starts, the parasites have usually left their hosts. Therefore it is important to investigate the patient's environment and to identify the infested materials. We describe an outbreak of Pyemotes dermatitis in at least 16 persons, most of them warehouse workers in a hobby mail-order house. Infested decorative wheat was the source of the problem. Successful eradication was achieved by fumigation of the storage facilities with the insecticide methylbromide. Our cases demonstrate the importance of examination of environmental specimens for ectoparasites in cases of unexplained dermatoses. Biological agriculture avoiding insecticides may cause reappearance of this almost forgotten skin disease.

Abstract: The Pyemotid genera Pygmephorus and Pyemotes are redefined. The former is divided into two morphologically and ecologically distinct subgenera, Pygmephorus sens strict. and Pygmephorellus subgen. n. Three new species, Pyemotes parviscolyti, Pygmephorus (subgen. Pygmephorellus) bennetti and P. (P.) brachycercus are described.