500 PRO'OEEDINiGS OF THE NATIONAL MUSEUM vol. oi 



is developed there. Inner margin of ventral surface of ischium 

 with an anteriorly corneous spine- or pointed-scale-tipped tubercle 

 at anterior end, and a lower, likewise corneous spine-tipped tubercle 

 at posterior end; two slight, at times almost imperceptible undula- 

 tions, or slight low swellings, may occupy the interspace. 



Anterior dorsal angle of epimeron of second (in lateral view, ap- 

 parent first) abdominal somite rounded off, yet armed on its anterior 

 margin, to the right, with two corneous spinules or denticles set quite 

 close together, to the left with one. 



Holotype. — The largest of four males from Humahuaca, Jujuy, 

 Argentina (M, A. C. N. No. 8837) measuring about 28 mm. in length 

 of carapace and rostrum together; the other three males of the type 

 lot measure respectively 25.0, 24.5, and 17.5 mm. 



Remarks. — This species and A. jujuy ana so resemble each other in 

 general appearance that one cannot escape the conviction that they 

 may be very closely related in spite of the fact that A. humahuaca 

 possesses a palmar crest and has a very bluntly ridged rostrum, char- 

 acters definitely differentiating the two. Geographically in the 

 Province of Jujuy these species are found scarcely more than 70 

 miles apart, but environmentally, or at least climatologically, they 

 are far removed one from the other. At Humahuaca the annual 

 rainfall totals only 6.11 inches^^; five months. May to September, 

 are without any precipitation whatsoever, while January, the wettest 

 month, has a rainfall of but 3.27 inches. At Juiuy, on the other 

 hand, the total is 29.26 inches ; no month is wholly without some pre- 

 cipitation, although this may fall as low as 0.12 inches in August; 

 the wettest month, January, marks a high of 6.65 inches, more in one 

 month than Humahuaca receives in a year. 



Distribution. — Other than the holotype and three paratypes from 

 Humahuaca, Province of Jujuy, Argentina, I have seen but one other 

 specimen, a female of 22.0 mm. in length of carapace and rostrum 

 taken together. This particular specimen was found in a bottle con- 

 taining two other specimens specifically different, together with a 

 detached cheliped. One of these specimens was selected as the type 

 of A. affinis (M. A. C. N. tag No. 9817) , the loose cheliped (M. A. C. N. 

 tag No. 4186) represents the same species; the remaining specimen 

 proved to be a male Aegla abtao (28.0 mm. in length of carapace and 

 rostrum). This lot of material certainly contains a mixture or else 

 one or both of the labels may be misattached. In the catalogs of the 

 Museo Argentino Ciencias Naturales entry No. 4186 reads simply 



" The fibres on precipitation given in this paragraph were taken from W. W. Reed's 

 undated, bound, typewritten manuscript, "Distribution of Precipitation over the Earth," 

 lent me by the Library of the United States Weather Bureau, through the kindness of 

 Miss Rose Vickers, librarian. 



