456 
W.A. Shear 
known from the eastern coastal regions of 
Australia (Shear 1974; Cantrell 1980), it only 
remained to find an acropsopilionine as a relict in 
Western Australia. The requisite specimens were 
collected at Torbay Head in 1987, and at additional 
localities in southern Western Australia in 1995. 
SYSTEMATICS 
Family Caddidae Banks 
Subfamily Acropsopilioninae Roewer 
Hesperopilio gen. nov. 
Type species 
Hesperopilio mainae sp. nov. 
Etymology 
From hesperus, the west, and opilio, a shepherd, 
used as a combining stem in this group of 
harvestmen. The gender is masculine. 
Diagnosis 
The peculiar features of the palpus separate this 
genus from all other acropsopilionines: the femur 
lacks ventral spined tubercles and the tibia and 
tarsus are much reduced. Specifically, the reduction 
of the tarsus to a small appendage of the tibia and 
(in females) the shortened, swollen, globular tibia 
with many glandular setae, are not duplicated 
anywhere in the family. Austropsopilio have 
somewhat reduced tarsi, but the tibiae retain setose 
lobes and are normally cylindrical; in Acropsopilio, 
the setose lobes of the tibia are usually absent, but 
the tarsus is not reduced. Caddella species have 
essentially unmodified palpal tibiae and tarsi. 
Males are known only in Caddella and 
Austropsopilio; the penes are complex, with 
accessory spines, and often exhibit torsion. The 
penis of Hesperopilio mainae is simple and 
acuminate, somewhat recalling the same organ in 
Caddo agilis (Gruber 1974). While some species of 
Austropsopilio have tuberculate bodies, none have 
the rows of tubercles above the eyes found in 
Hesperopilio. 
Remarks 
Cokendolpher and Maury (1990) claimed that 
Austropsopilio males were unknown until they 
found some in Queensland Museum collections 
(they excluded A. fuscus, males of which were 
described by Hickman [as Tasmanopilio fuscus, 
Hickman 1957]). They did not describe the 
specimens, but James Cokendolpher very kindly 
compared a drawing of the penis of H. mainae with 
his drawings of that of Austropsopilio species, and 
agreed that the Western Australian species 
represented a new genus. He pointed out that in 
Caddella and Austropsopilio, the other two genera 
with reduced palpal tibiae and tarsi, the penis is 
complex and spiny. 
The palpi of Hesperopilio mainae converge to some 
degree on the palpi of the unrelated family 
Sabaconidae, in which a small tarsus reflexes 
against a swollen tibia, heavily set with glandular 
setae. Sabaconids collect prey by using the palpi as 
'flypaper' and then rake them off the palpi with 
specialized cheliceral combs. While glandular 
Figures 1, 2 Hesperopilio mainae n. gen., n. sp., 6 . 1, body, dorsal view; 2, same, lateral view. Scale line = 0.5 mm. 
