74 
TRAUB & AUDY 
Trombicula (Leptotrombidium) deliensis Walch, 1922 (fig. 70-78, pp. 68, 69). 
Diagnosis of Larva. — Palpal formula N/N/BNN. Palpal claw 3-pronged. Galeal seta 
plumose. Scutum rather rectangular, but lateral margins somewhat concave, posterior margin 
slightly convex. Bases of sensillae inserted only slightly anterior to level of PLs. Sensillae 
with proximal portion nude; apical third sparsely plumed. PL seta less than half again as 
long as SD; not much longer than AL, subequal to AM. Scutal setae fairly well plumed, 
the barbs short. Dorsal setae resembling those of scutum; about 28-32 in number, the rows 
nearly always commencing 2. 8. 6. 6. With 12-14 ventral setae plus 6-8 caudals (postanals). 
Sensory setae of legs as in T. baluensis n. sp. 
Recent studies of the akamushi- group have shown that the ratio PW/Coxa-II (see fig. 76) 
gives a valuable and apparently reliable means of separating T. deliensis from T. akamushi. In 
a number of series of T. deliensis , this ratio averaged 1.16 and was consistently well below 1.30, 
while in T. akamushi taken from many different sources it ranged between 1.30 to 1.50 (mean 
1.40). Further details of this study are being made the subject of a paper now in preparation. 
Use is made of the PW/Coxa-II ratio in a following study by Traub and Evans (1953, this 
Study , p. 89). 
Standard Measurements in Microns, T. deliensis from Borneo. 
AW 
PW 
SB 
ASB 
PSB 
A-P 
AL 
AM 
PL 
DS 
PW 
Cox II 
PW 
SL> 
PW 
ASB 
PW 
A-P 
Alean 
55 
68 
26 
24 
15 
32 
46 
57 
53 
54 
66/57 
= 1.16 
1.65 
2.8 
2.0 
Range ( + or — ) 
6 
7 
3 
3 
2 
3 
4 
5 
4 
4 
0.07 
0.07 
0.05 
0.03 
Records. — T. deliensis has been taken by us on Mt. Kinabalu from the following hosts : 1) 
at Tenompok, at an elevation of about 4,500 feet on Rattus rattus diardii, Rattus exulans , 
Callosciurus lowii , Nannosciurus whiteheadi , Dremomys everetti , Crocidura sp., Hylomys suillus , 
Tupaia minor , ?nd Tupaia montana. 2) At Lumu Lumu, elevation 6,300 feet, on Rattus white- 
headi. 3) At Kamborangah in moss-forest, elevation 7,800 feet, on Tupaia montana and 
Dendrogale melanura baluensis. T. deliensis was also found in numbers on a variety of hosts 
in the coastal collections near Menggatal and Beaufort as well as in Sarawak. 
Trombicula (Leptotrombidium) akamushi Brumpt, 1910 (figs. 79-86, pp. 70, 71). 
Diagnosis of Larva. — Closely resembling T. deliensis but the PW/Coxa-II ratio ranges 
between 1. 30-1. 50 ; there are usually 35-40 dorsal setae, commencing as a rule 2.10.8., but 
Kinabalu specimens frequently are 2.8.6. PW typically is over 72 ; and the sensillae bases 
are usually clearly inserted well anterior to the fine of PLs. 
On Kinabalu, we have collected typical T. akamushi from chicks of an unidentified ground 
bird, from Macaca irus and the tree shrew, Tupaia minor , at Tenompok, from Rattus rattus 
diardii in the vicinity of Bundu Tuhan, elevation 4,000-5,000 feet, and from Tupaia montana 
at Kamborangah, elevation 7,800 feet ; but not from the coastal collections. No specimens 
of T. akamushi have been found in the considerable collections from Sarawak made in collabo- 
ration with Mr. Tom Harrisson. 
A form with dorsal setae generally 2.8.6.., resembling T. akamushi f. obscura of Womersley, 
was widespread and common. Comments on this form are being withheld pending further 
detailed studies of the larvae and nymphs. 
STUD. INST. MED. RES. 
