364 A YEAR OF COSTA RICAN NATURAL HISTORY 



as these American forms are termed by different authors, 

 are slender creatures, members of the family Buthidae. 

 The family is characterized by having two, not one, spurs 

 or spines in the membrane between the last and next to the 

 last section of each leg, and the sternum (or middle plate 

 on the under side of the body on the line between the third 

 and fourth legs) approximately triangular in shape. The 

 pincers at the tip of the first long pair of limbs (pedipalps) 

 by which Centrums, like other scorpions, grasps its prey, 

 have on the inner surface of each jaw, a number (seven to 

 nine) of short rows of small uniform teeth. These median 

 rows run slightly obliquely, so that they are not in contin- 

 uation of one another nor, on the other hand, do they more 

 than barely overlap. On each side of;»these median rows 

 is another row of fewer, less closely-set teeth, where a larger 

 tooth alternates with two or three smaller ones. Other 

 genera of scorpions have the teeth of the pincer-jaws ar- 

 ranged in other ways — one wonders whether there is any 

 advantage or adaptation in the arrangement to the special 

 mode of life of the animal. Margaritatus belongs to a group 

 within the genus Centrums having seven or eight rows of 

 median teeth, while C. bicolor, which appeared in the office at 

 Philadelphia South farm (see page 319) has nine such rows. 



When we arrived at the clubhouse on December 19, some 

 members of the club were there but returned to San Jose in 

 the afternoon. They had shot a doe that morning, about 

 half an hour's walk distant; it was hanging under the veranda 

 in front of the Custodio's house and went off to San Jose 

 with the hunters. 



West of the club's land were maize and plantain fields 

 and pastures. In December the former looked like harvested 

 fields at home after the crop has been removed and weeds 

 have grown up, reached their prime and dried; some of the 

 weeds were very familiar too, such as the "mozote" or 



