1965] 
Reiskind — Genus Sicarius 
223 
Step 7 or beginning of Step 8. This same behavior is also observed 
in a more immature specimen of Sicarius sp. 2. In Sicarius sp. 1 
there is usually no pause during Step 7 or between Steps 7 an d 8. 
The first legs are buried (Step 8), as are the second and third 
legs, by forward, downward, jerky movements. Often the legs are 
only partially buried, leaving the patella and part of the femur ex- 
posed (arrows in Fig. 7). 
Step 9 begins with either the right or left second leg (usually the 
right). After throwing sand forward, covering the exposed part of 
the first leg of its side, each leg buries itself (Steps 9-12). 
The third leg actions (Steps 13-16) resemble those of the second 
legs with either side beginning first. This usually completes the bury- 
ing though there are often adjustments in the fourth legs, and some- 
times fourth leg actions similar to the second and third legs. 
The above description is of the complete, fixed behavior observed 
in both species of Sicarius. But often the burying stops prematurely, 
usually in response to some environmental difficulty — e.g., a cramped 
position or an unsatisfactorily dug hole. At other times cause of 
cessation before completion is unidentifiable. 
To summarize, two species of Sicarius from South America show 
basically similar, fixed self-burying behavior with only one, distinct, 
qualitative difference (in Step 7). This fixed ethological character 
appears to be of potential systematic value. 
The author wishes to thank Dr. H. W. Levi for suggesting this 
topic, collecting the organisms, and giving complete support in all 
phases of this work; Dr. W. K. Weyrauch for bringing this specific 
problem to notice: and both Drs. J. Abalos and P. Aquilar F. for 
invaluable aid in the field work. 
Explanation of Plate 17 
Figs. 7-12. Self-burying of Sicarius sp. 1, steps 8, 9, 10-12, 16 (see Table 
1 and text for details). 
References 
Bonnet, P. 
1945-1959. Bibliographia Araneorum, Les Artisans de I’Imprimerie 
Douladoure, Toulouse. 
Cazier, M. A. and M. A. Mortensen 
1962. Analysis of the habitat, web design, cocoon and egg sacs of the 
tube weaving spider Diguetia canities (McCook). (Aranea, Di- 
guetidae). Bull. So. Calif. Academy Sciences 61 (2) : 65-88. 
