Mygalomorphe tn the British Museum. 225 
Aviculariine. But the spinning-mammille appear to be 
constructed differently from the plan that is characteristic of 
either of these sections. The posterior mamille are short, 
the segments being thick and gradually decreasing in length 
from the first to the third; the first, moreover, is much 
thicker at its distal end, while the third, on the contrary, is 
pointed and conical; the anterior spinners are slender, cylin- 
drical, about half the length of the basal segment of the 
posterior, and separated by a space which is equal to about 
twice their own thickness. There is no true rastellum on the 
mandible, although the sete above the fang seem stout at the 
base and the scopule of the feet are very scanty, yet appa- 
rently entire. «The maxille are basally spinulose, and there 
are a few (two or three) apical spinules on, the labium. I 
think it is probable that the genus will prove to be related to 
some of the American species of Leptopelmatee. 
Idiommata Blackwallii, Cambr. (Proc. Zool. Soc. 1870, 
p. 154).—The type of this species (a male) has Wood-Mason’s 
stridulating-organ well developed. The female is unknown 
to me, and so also are the males of the other Australian 
species that have been referred to Jdiommata. But the females 
of what I believe to be reticulatum of L. Koch, as well as of 
other species, show no trace of this organ. It is possible, 
therefore, that it may be present only in the males of this 
genus. ‘This, however, does not seem probable; so that the 
safer course is to regard the two sets of species—z. e. that 
typified by Blackwallit and that by reticulatum—as generically 
distinct. The latter in that case will probably have to take 
the name Encyocrypta. 
Ischnocolus obscurus, Auss. (op. cit. p. 171), from Bogota, 
appears to be congeneric with the species previously named 
by the author Hapalopus formosus, of which the Museum has 
a single female specimen from the locality just mentioned. 
Ischnocolus sericeus, id. (op. cit. p. 119), from Yucatan, 
is based upon a young specimen of undetermined genus. 
Ischnocolus hirsutus, id. (op. cit. p. 170), is based upon 
a young specimen belonging probably to some species of 
Lasiodora. 
Ischnocolus parvus, Keys., is apparently the young of a 
species of Hurypelma. 
Ischnocolus gracilis, Keys. (‘ Spinnen Amerikas,’ iit. p. 11), 
