370 
PACIFIC SCIENCE, VoL XII, October, 1958 
ferences between them appear to be of truly 
specific nature. They can be differentiated 
immediately on the basis of the chaetotaxy 
of the postscutum. In view of the variation 
noted in P. hidactylus it should be expected 
that exceptional forms might be found which 
have four setae on the postscutum, although 
none has been seen by the writer. However, 
even if this were to occur, the position of the 
lateral setae in P. quadriseta is very character- 
istic, these forming nearly a straight line with 
the medial setae. There are other differences 
too, of a more relative nature, in the propor- 
tions of the scutum and postscutum and the 
positions occupied by the specialized setae of 
tarsi I and II. These are summarized in the 
preceding table of variants of larval characters. 
REFERENCES 
Bruyant, L. 1910. Description d’une nou- 
velle larve de Trombidion ( Paratrombium 
egregium , n. gen. n. sp.), et remarques sur 
les Leptes. Z 00 L Anz. 35: 347-352. 
Feeder, Z. 1952. Legatura mtre Genurile Di- 
nothrombium Oud. 19 10 si Parathromhium 
Bruyant 19 10 si descrierea lui Parathromhi- 
um insulate (Berlese) 19 10 var. divisipilli 
Feider 1948. Buletin Stiintific Sectiunea de 
Stiinte Biologies , Agronomics , Geologies si Geo - 
grafice 4(4): 956-970. 
Newell, I. M. 1957. Studies on the Johns- 
tonianidae (Acari, Parasitengona) . Pacific 
Sci. 11(4): 396-466. 
Oudemans, A. C. 1910. Acarologische aan- 
teekeningen. XXIV. Ber. Nederland. Ent . 
Ver. 3: 103-109. 
• 1912. Die bis jetzt bekannten Larven 
von Thrombidiidae und Erythraeidae, mit 
besonderer Berucksichtigung der fur den 
Menschen schadlichen Arten. Z 00 L Jahrb 
Sup. 14: 1-230. 
Thor, Sig., and C. Willmann. 1947. 'From- 
bidiidae. IN Das Tierreich 71b: 187-541. 
Womersley, Herbert. 1939^. Further notes 
on the Australian Trombidiidae with de- 
scription of new species. Roy. Soc. So. 
Austral ., Trans . 63(2): 149-166. 
