FLORIDA SPIDERS IN THE RUFUS GROUP IN THE 
GENUS PHILODROMUS (ARANEAE: THOMISIDAE) 
By C. D. Dondale 1 
Canada Department of Agriculture 
The most useful means of classifying the North American species 
of Philodromus is to divide them into three groups according to 
carapace proportions, number of eye tubercles, and features of the 
external genitalia. The aureolus group (Dondale, 1961 ) and the rufus 
group (defined below) account for the majority of the species, while 
the remainder (e.g., P. alascensis Keyserling and P. virescens Thorell) 
comprise a small third (or possibly a third and fourth) group char- 
acterized in part by modifications in the tibial apophyses of the male 
palpus. In particular, the ventral apophysis is either in the form of 
a short, rounded lobe or entirely absent. 
The rufus group can be defined briefly as follows: males rarely 
exceeding 3.5 mm in body length, and females rarely 4.5 mm; carapace 
usually longer than wide, and all the eyes except the anterior medians 
seated on small tubercles; ventral tibial apophysis of the male palpal 
tibia elongate, soft, and flattened ; spermathecae of females situated an- 
terior to rather than at, the genital groove. 
The group presents a special challenge to the taxonomist because 
of the presence of several complexes of closely-similar forms. Some 
of these problems are discussed in this paper, particularly those 
involving the Florida peninsula and adjacent parts of the continent. 
There are seven members of the rufus group in Florida. P. placidus 
Banks, P. marxi Keyserling, and P. imbecillus Keyserling range widely 
over North America and extend various distances into the Florida 
peninsula, although rarely south of approximately 28° north latitude. 
P. montanus Bryant and P. floridensis Banks are restricted to the 
southeastern United States. P. peninsulanus Gertsch and P. bilineatus 
Bryant are known only from the southern tip of Florida. 
Philodromus placidus Banks 
Synonymy. See Kaston (1948), Roewer (1954), and Bonnet 
( 1958 ). 
Description. See Kaston (1948). 
Range. Alaska to Nova Scotia, south to Vancouver Island, Utah. 
Vera Cruz, and Florida. 
’Entomology Research Institute for Biological Control, Research Branch, 
Canada Department of Agriculture, Belleville, Ontario. 
Manuscript received by the editor September 14, 1962. 
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