4, ARANEIDEA. 
from the Ethiopian and Oriental regions it is, so far as I have had opportunity of 
observing, entirely absent. 
Passing on from these broader considerations of distribution and narrowing our 
investigations down to the Central-American and adjacent regions, with whose fauna we 
are more immediately concerned, we must also remark that so far, in the absence of 
sufficient data, we are not justified in speaking too positively as to the distribution of 
different families and genera. 
- The only further feature that strikes one in connection with distribution of the 
Mygalomorphe in Central America is the small number of the Ctenizide and 
Dipluride and the greater number of the Theraphoside, especially of the genus 
Eurypelma and some allied forms. This feature, however, is probably due entirely 
to the fact that the trapdoor spiders are not easy to find, while the others force them- 
selves more or less on the observation, and hence are more numerously represented in 
the bottles of the collector. 
The number of representatives of this section hitherto taken is so exceedingly 
small in comparison with the enormous extent of the region that one cannot venture 
to speak with any great confidence on the subject of the proportional distribution of 
different families and genera. 
In conclusion, however, it may be remarked that one genus only occurs north of the 
fortieth parallel, viz. Euagrus (rubricularis, Sim.), which has been recorded by 
Dr. Geo. Marx from Idaho. Bothriocyrtum californicum, O. P.-Cambr., is reported as 
occurring in Utah, and Myrmeciophila atkinsonii, Sim., in Virginia. Eurypelma does 
not apparently occur further north than Arizona and California (where forms are apt to 
creep up the coast-line), New Mexico, and Texas. Tapinauchenius has been recorded 
from as far north as “Indian Territory” by Dr. Marx, which, if the identification be 
correct, is somewhat surprising; while Avicularia, Sericopelma, and Xenesthis, genera 
essentially equatorial, have not been recorded further north than Panama. 
MYGALOMORPH &, Pocock. 
The plane of the joint of the mandible with the carapace nearly vertical, the fang closing almost directly 
backwards. Four lung-sacs, the posterior widely separated, close behind the anterior, with distinct 
transverse opercula, Spinning-mamille four, rarely six. 
This large and very distinct section may conveniently be subdivided into more or less 
compact and natural families, though of course intermediate forms occur in most cases, 
which partaking of the characters of two families cannot be classed with either. The 
families represented in Central America may be briefly characterized as follows :— 
A. Tarsi without claw-tufts ; inferior claw nearly always distinct. 
a. Base of mandible furnished at the apex with a more or less well- 
developed rastellum. Spinning-mamillz short, stout, and closely 
situate at the base. . . . + ee ee ee ee we we 6 Crentzi1ve, Thor. 
