404. SANITARY ENTOMOLOGY 



in man and animals. The BICHO-COLORADO ITCH is caused by the 

 mite Tetranychus molestissimus Weyenbergh, which thrusts its hypos- 

 toma into the skin of man and animals in Argentine and Uruguay. In 

 Europe a similar dermatosis is caused by the related species T. telarius 

 Linnaeus, variety russeolus Koch. These two species belong to the family 

 Tetranychidae. 



The disease known as "GONONE" in Celebes and New Guinea is 

 caused by the Trombidian mites Microtrombidium wichmanni Oudemans 

 and Schongastia vandersandei Oudemans. This attack occurs both on 

 man and animals. In Europe and America attack by various allied 

 species is very common. The ordinary name for the attack is RED 

 BUGS or CHIGGERS. The principal species which have been described 

 as causing this attack are Microtrombidium tlalsahuate Lamaire in 

 Mexico ; Trombidivmi holosericewm Linnaeus, T. inopinatv/m Oudemans, 

 and T. autummalis Shaw in Europe; T. batatas Linnaeus in the West 

 Indies ; Leptus americanus Riley, and L. iritans Riley in North America ; 

 and also Trombidium striaticeps H. & 0., Metatrombidium poriceps H. 

 & O., Microtrombidiium pusillwm Hermann, and Allotrombidium fuligvno- 

 sti/m Hermann. The attack of chiggers is very painful and also difficult 

 to relieve. Dusting of flowers of sulphur in the clothes is a good pre- 

 ventive. I have had fairly good success in taking a hot bath immediately 

 after coming from the field and then rubbing in ammonia. 



The allied species Leptiis akamushi Brumpt not only causes a 

 dermatosis, but also a definite disease which will be treated in a later 

 paragraph. This is a Japanese species. 



A troublesome acarine dermatosis, which frequently causes swelling 

 which may be dangerous, is caused by Holothyrus coccinella Gervais m 

 Mauritius, which normally attacks dogs and geese, but also attacks 

 children. 



In the family Parasitidae quite a number of species are charged with 

 causing dermatosis. Dermanyssus gallinae Redi and D. hirundinis Her- 

 mann, common avian parasites may also cause dermatosis in man. D. 

 gallinae sometimes causes papular eczeraatous dermatosis. Liponyssus 

 bacoti Hirst, a rat parasite in Australia, Africa and South America, 

 occasionally causes dermatosis of people working in stores and granaries. 



URTICARIASIS is caused by various species of the family Tar- 

 sonemidae. The mite, Pediculoides ventricosus Newport, causes a disease 

 known under a number of diff^erent names, as GRAIN ITCH or ERY- 

 THEMA URTICARIA. This mite becomes globular and reproduces 

 its young at a very rapid rate. It burrows under the skin and is very 

 painful. Many workers in harvest fields are attacked by this mite, espe- 

 cially in Europe. It occurs quite commonly in America. A similar der- 

 matosis is caused by Tarsonemus wncinatus, T. intectus, and Crithoptes 



