SELF-BURYING BEHAVIOR IN THE 
GENUS SICARIUS (ARANEAE, SICARIIDAE) 1 
By Jonathan Reiskind 
Biological Laboratories, Harvard University 
The family Sicariidae has only recently been recognized as a poly- 
ph}detic taxon. Although it is difficult to establish natural limits, 
Gertsch (1949) has more logically separated the group into the 
Scytodidae, Diguetidae, Plectreuridae, Loxoscelidae, and Sicariidae 
(s.s.), all of which had been subfamilies of the Sicariidae (Bonnet, 
I 945- I 959). These five families are differentiated distinctly and 
naturally by their ethological characters. The sole reason for their 
being previously lumped is their common possession of simple geni- 
talia. This character is automatically considered primitive and hence 
these spiders were “representative of the ancestral stock.” Their 
genitalia may, indeed, be relatively unchanged from the primitive 
form but in many other characteristics these spiders are quite spe- 
cialized and advanced and bear very little resemblance to the an- 
cestral stock. One can readily talk of “primitive characters” but 
rarely of “primitive, living organisms.” 
Some of the highly specialized ethological characters of the 
families mentioned are: 
Scytodidae: Prey captured by spitting gummy substance from 
chelicerae; egg cocoons carried; spiders sometimes live in web on 
stones and rocks or in houses (Dabelow, 1958). 
Diguetidae: Tubular cocoon constructed from silk and detritus 
and suspended by web in vegetation over sheet web ; layers of egg 
sacs in a cocoon which also acts as retreat for spider (Cazier & Mor- 
tenson, 1962). 
Plectreuridae: Low lying mesh web, associated with tubular re- 
treat under rock or debris, in which spider sometimes hangs up-side- 
down; eggs in loose cocoon (W. Eberhard, pers. comm.; Gertsch, 
1958 ). 
Loxoscelidae: Large, irregular sheet web (hackled band appear- 
ance) ; eggs in loose sac. 
1 Research a by-product of National Institute of Health Grant No. AI- 
01944 to Dr. H. W. Levi. 
Manuscript received by the editor October 15, 1965. 
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