858 THE AMERICAN NATURALIST. [Vor. XXXIV. 
2. While the Orthoptera, as a rule, are large or medium- 
sized insects, both Myrmecophila and Attaphila are so far 
below even the average stature of insects of this order that we 
must conclude either that they have become reduced in size 
secondarily in adaptation to their present habitat and compan- 
ionship, or that they were originally diminutive species, and, 
for that very reason, better able to enter into symbiotic rela- 
tionship with the ants. The latter alternative seems to be the 
more probable. 
3. The eyes of Attaphila are vestigial in both sexes. This 
is indicated by their very small size, the greatly reduced number 
of their facets, and their irregular orbits (Fig. 6). There are 
scarcely more than seventy ommatidia in either eye, whereas, 
according to Miall and Denny,! there are 
about eighteen hundred in the eye of the 
common cockroach (Periplaneta orientalis), 
and some other species have even larger eyes, 
and therefore, in all probability, a still greater 
number of ommatidia. The vestigial condi- 
tion of the eyes in Attaphila is of interest 
because it shows that the insect has become 
thoroughly adapted to living in the dark. It 
hc dahil dacs is, in fact, a truly cavernicolous form, living 
cola n. sp., eye of adult in caves constructed by its emmet hosts. 
The reduction of the eyes has not, however, 
proceeded so far as in another diminutive cockroach, Vycticola 
Simoni, which is known to inhabit caves in the Philippine 
Islands. 
4. Additional evidence of the lifelong confinement of Atta- 
phila to the chambers of the ants’ nest is seen in the extremely 
rudimental condition of the tegmina and wings in the adult 
male, and the complete absence of these structures in the adult 
female. There can be no doubt that the specimens figured 
(Figs. 3-5) were mature, as the testes of the male contained 
ripe spermatozoa, and the ovaries of the female contained large, 
elliptical white eggs. The oótheca of this form must be an 
1 Studies in Comparative Anatomy. III. The Structure and Life History of 
the Cockroach, p. 99. London, 1886. 
