CHAMBERIvIN : ARACHNIDA OF PERUVIAN ISLANDS. 43 
reddish brown hairs intermingled; no definite patterns. Upper margin 
of furrow of chelicera with three teeth, the lower with none. Tibia 
I armed beneath with 3-3 spines, laterally armed as is also patella I. 
Tibia IV armed above. Claws of last legs armed with six teeth which 
decrease in length proximad. Characterized especially by the form of 
the tibial apophysis and the structure of the tarsal bulb which are 
represented in fig. 9. 
Length, 5 mm. Length of cephalothorax, 2.5 mm. Length of 
tib. + pat. IV, 2.2 mm. 
Locality. — Peru: Mazorca Id. Two males were taken Dec. 29, 1919. 
Type, Museum of Comparativ^e Zoologx-, 525. 
This appears to be the first species of the genus recorded from South 
America. 
ACAKINA. 
ARGASIDAE. 
Ornithodoros tulaje, (Guerin-Meneville). 
Argas hilaje Guerin-Meneville, Rev. Mag. Zool., 1849, ser. 2, I, ]). 
342. pi. 2. 
About a .score of si)ecimens of typical form were taken on Lobos de 
Tierra Id. in Jan., 1920. The larger specimens are 5 mm. in length. 
Dr. Murphy noted that the specimens are pale in life, darkening in the 
preservative. One specimen 3 mm. long was taken from the body of a 
nestling booby, Siila iiebouxi, the first record of this bird as a host for the 
species. Six-legged larval specimens, of which many were taken from 
the plumage of the adult booby, .seem to be this species. 
Ornithodoros amblus, sp. nov. 
PI. 4, fig. 10. 
Clo.se in general structure to O. tulaje. It is a larger form, the types 
ranging up to 7.2 mm. in length and 4.2 mm. in width, whereas 6 mm. 
is the maximum recorded for tulaje with most individuals considerabh' 
smaller than this. A readily marked difference in the present form is 
that the anterior end of the body is simply obtasely angular, not with the 
subconical form characteristic of tulaje, the margin each side of the med- 
