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 Myrmecice 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 Mutillidce, 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 tibiae. Such is especially the case in the typical 

 Myrmecice, 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 calcariae 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 Mutillidce, and 

 dependent upon their habits of burrowing in sand. The ab- 

 sence of these appendages consequently either proves that 

 Typhlopone is an ant or a parasitic Mutillideous insect ; none 

 such, however, have as yet been observed amongst the Mutil- 

 lidce ; indeed it is not only contrary to analogy to suppose that 

 the female of a parasitic aculeate Hymenopterous insect should 

 want wings, (its oeconomy 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. 



