NATURAL HISTORY OF THE SPIDER 
HYPOCHILUS THORELLI MARX (HYPOCHILIDAE) 1 
By Ian C. Fergusson 
Department of Biology, 
Western Carolina University, Cullowhee, N. C. 2 
Introduction 
Hypochilus is regarded as the most primitive of the three “hypo- 
chilomorph” spider families: the Hypochilidae, Austrochilidae ( = 
Thaididae) and Hickmaniidae (Marples, 1968). These small, close- 
ly related families exhibit character states resembling both those of 
the primitive mygalomorph spiders (suborder Orthognatha) and the 
araneomorph spiders (suborder Labidognatha) . They are consid- 
ered to be the most primitive araneomorphs (Gertsch, 1958; Mar- 
ples, 1968). The hypochilomorph families are geographic as well as 
phylogenetic relicts, being represented by limited populations in such 
widely-separated areas as the United States (Hypochilidae), China 
(Hypochilidae), Chile (Austrochilidae), and Tasmania (Hick- 
maniidae). Clearly, a better understanding of spider evolution may 
be gained from studies of hypochilomorph biology (Marples, 1968; 
Shear, 1970). 
The four known species of Hypochilus occur only in the United 
States. All are allopatric and are found only in mountainous re- 
gions. 
Most works on Hypochilus have used only morphological char- 
acters to determine the relationships of the Hypochilidae to other 
spider families. Though mention has been made of web structure 
(Comstock, 1940; Gertsch, 1958; Hoffman, 1963), only two in- 
vestigators (Kraus, 1965, and Shear, 1970, with Hypochilus gert- 
schi) have published additional behavioral data. Life history data 
on Hypochilus are virtually non-existent. 
The present study was undertaken to obtain information on the 
natural history (ecology, life history, and behavior) of Hypochilus 
thorelli. It is hoped that these data will contribute to an under- 
standing of the evolutionary history of Hypochilus and the Hypo- 
3 From a thesis presented to the graduate faculty of Western Carolina 
University in partial fulfillment of the requirements for the degree of 
Master of Arts in Biology. 
2 Present address: 524 Benton Street, Missoula, Montana 59801 
Manuscript received by the editor October 15, 1972 
179 
