A. C. OUDEMANS. ACARI. 149 



is so abundant that I will not trouble my readers with it. It has been proved that also the 

 larva of Thrombïdium fuliginosum (Herm.) is guilty to the itch. 



Since New Guinea and the surrounding Isles are visited by Europeans, thèse often 

 complain of a kind of itch, caused by some invisible „insect" or „tick" on the legs of those 

 who go through the grass and through the forests. Ail vvhat I communicate hère about this 

 terrible vexation I am indebted to Mr. G. A. J. VAN DER Sande, Physician to the Dutch 

 Expédition of 1903, to whom I offer my sincère thanks. 



The oldest informations about the New Guinea harvest-mite, Thrombidium van der 

 Sandeï Oudms. (see page 131), are procured us by J. H. DE BOUDIJCK BASTIAANSE, captain 

 of the Iris. Now and then lie made little trips of one day on the shore and in the forests ; 

 returned he ever and anon was plagued by an itch. Also he mentions that in différent indi- 

 viduals the itch was not equal ; in some individuals the itch was intense and lasting, whilst 

 in others it soon diminished. The appropriated treatment in some instances soon cured; in 

 others it healed very slowly. His work is entitled: Voyages faits dans les Moluques à la 

 Nouvelle Guinée et a Célébes : Paris, 1845. On p. 19 we read : 



„Le lendemain nous ressentîmes tous une terrible démangeaison dans toutes les parties 

 du corps et particulièrement aux jambes." 



and on p. 26 : 



_La soirée était avancée quand nous fûmes de retour à bord. Cette fois encore, comme 

 dans notre excursion précédente nous sentîmes une forte démangeaison principalement aux 

 jambes. Notre médecin qui avait essayé de quelques remèdes extérieures, en souffrit plus 

 longtemps que nous, qui avions abandonné à la nature le soin de notre guérison." 



The well known explorer C. B. H, VON ROSENBERG tells us in his „Reistochten naar 

 de Geelvinkbaai op Nieinu-Guinea in de jaren 186c en iSjo ; 's Gravenhage, 1875, p. 40 : 



.Eene menigte Iastige insecten maakten ons verblijf tôt eene hel. Onder deze insecten 

 speelden kolossale spinnen (Epeira), pissebedden (Asellus) en eene soort van aardmijten eene 

 hoofdrol, welke laatste onder en tusschen het bevloeringshout gezeten, zich reeds den tweeden 

 dag in de kleeren en op het bloote lijf genesteld hadden, met geene mogelijkheid te ver- 

 drijven waren en door hunne beten een ondragelijken jeuk veroorzaakten." 



This happened on a journey at Rumsaro in the Geelvink Bay, February, 1869, where 

 he was obliged to debark after the ship was pushed on a riff. The wood of the floor origin- 

 ated from a shed, in which he temporarily sheltered, and consisted in trunks and branches 

 laid down disorderly on the wet ground. That the mites attacked the whole body is most 

 probably the resuit of the sleeping on this floor. For the first time the itch is attributed 

 to a créature and exactly to the real cause, a kind of mite, an earth-mite. It seems that 

 VON ROSENBERG lias observed the mite, if not, he at least has hit the nail on the head. 



According to P. J. B. C. ROBIDÉ VAN DER Aa, Reizen naar Nederlandsch Nieiav-Guinea 

 ondernomen op last der Regeering van Nederlandsch- Iridié in de jaren i8ji, i8j2, i8jj — i8j6; 

 's Gravenhage, 1879, Mr. J. E. TEYSMANN made, 1871, on board of the Dassoon his first 

 scientific visit to New Guinea. From Salawatti TEYSMANN in September of that year visited 



