84 Mr. J. O. Westwood on the Genus Typhlopone, 
the locomotive organs and their action. In wingless insects 
motion is of course performed by the legs alone, and for this 
end the thoracic segments are nearly equally developed, espe- 
cially when the legs are nearly of equal size. This is especially 
to be seen in the typical Myrmecie of New Holland, in which, 
from the elongated form of the body, each segment is neces- 
sarily drawn out to its full length of development. Here we 
find the collar of the prothorax large, oval, longitudinally or 
obliquely striated, emarginate behind, receiving the front of 
the mesothorax in the emargination, and which, as well as 
the metathorax, is transversely striated. The examination of 
a very few species of neuter Ants will show the more or less 
gradual coalescence of the meso- and metathorax; the pro- 
thorax, however, remaining always most distinct and large, 
and such is exactly its structure in Typhlopone. In the apte- 
rous females of the typical Mutillide, on the other hand, all 
the segments are consolidated into a single mass. 
Of the legs, I shall merely observe, that the employment of 
the character to be derived from the calcaria is fallacious, be- 
cause although many Ants possess but one spur to each tibia, 
there are certainly many which possess two to each of the 
four hind tibiz. Such is especially the case in the typical 
Myrmecia, in which one of the two spurs of each of the four 
hind legs exhibits a very beautiful structure. At the same 
time, there are others, such as Cryptocerus atratus, Pheidole 
providens, &c., which are entirely destitute of calcarize in the 
four hind legs. And it is moreover to be observed, that both 
in respect to the spurs and the tarsal ungues, the formation 
is identical in all the three kinds of individuals of Myrmecia, 
as well as in both sexes of Thynnus, and even in both sexes of 
Mutilla*. In Typhlopone the ungues are perfectly simple : so 
also may we reasonably expect them to be in their males. 
Another circumstance also deserves to be noticed, namely, 
the entire want of cilia or bristles on the fore legs of Typhlo- 
pone, a character found in the apterous female Mutillide, and 
dependent upon their habits of burrowing in sand. - The ab- 
sence of these appendages consequently either proves that 
Typhiopone is an ant or a parasitic Mutillideous insect ; none 
such, however, have as yet been observed amongst the Mutil- 
lide ; indeed it is not only contrary to analogy to suppose that 
the female of a parasitic aculeate Hymenopterous insect should 
want wings, (its ceconomy rendering the possession of them 
absolutely necessary for its existence,) but the habits noticed 
above are sufficient to disprove the supposition. 
* In both sexes of Mutilla Klugii, for example, each of the ungues of 
which is furnished with a remarkable seta, as long as the unguis itself. 
