with descriptions of several exotic species of Ants. 83 



Odontomachus armatus, Latr. (neuter = Daceton armigerum, 

 Perty), Cryptocerus atratus (female and neuter), Atta cepha- 

 lotes (female and neuter), and others, have only eleven jointed 

 antennae, the second joint being exposed. No previous au- 

 thor has noticed this curious circumstance, and Mr. Shuckard 

 stating that "this curtailment is never found in the apterous 

 social Heterogyna*" , thereon founds an unwarranted rela- 

 tionship with the Mutillidce. 



The situation of the antennae close to the mouth, and the 

 elongated basal joint with the following joint affixed so as to 

 form an elbow, are also characters which Typhlopone possesses 

 in common with the Ants. 



The mouth is remarkable for the extraordinary minuteness 

 of the palpi. The curtailed structure of the trophi (that is, of 

 the maxillae, labium and palpi) is stated by Mr. Shuckard pe- 

 culiarly to distinguish the Dorylida from both the Formicidce 

 and the Mutillidce. But this is not the case, as I have in- 

 stanced a considerable number of species of ants in which both 

 the maxillary and labial palpi possess much fewer joints 

 than the typical number (Tntrod. 2, p. 219.). 



The structure of the thorax is very interesting in Typhlo- 

 pone. Mr. Shuckard has, however, completely mistaken its 

 formation, considering the pro thoracic collar as the meso- 

 thorax, and overlooking the true mesothorax. This has evi- 

 dently resulted from the want of a careful examination of the 

 corresponding parts in the allied groups, and the absence of 

 generalization in the views taken of the thoracic organization ; 

 hence, therefore, the erroneous nature of the observations 

 which Mr. Shuckard has published relative to the supposed 

 peculiar distinction between Typhlopone and the other apte- 

 rous Heterogyna of both groups, and of the relation between 

 Typhlopone and the Dorylidce in this respect f. 



The principle upon which the variation in the development 

 of the thoracic segments is regulated, depends entirely upon 



* Mr. Shuckard has made some observations relative to the adoption of 

 the term Heterogyna of Latreille, contending that the term ought to be re- 

 tained for the Mutillidce, instead of being applied to the Ants, as it is by 

 Saint Fargeau and Haliday. It appears to me, however, that the term was 

 intended to apply either to the distinction which existed between the winged 

 females of Formica and the wingless females of Mutilla, or to the difference 

 between the winged females and the wingless pseudo-females of Formica. 

 In this latter sense the name is the most appropriate that could be applied to 

 the Formicidce as distinct from every other group of insects. 



f Amongst other things, Mr. Shuckard states that when the meso- and 

 metathorax are of unequal size in the winged males of Heterogyna, it is the 

 latter which is most developed, — a statement neither confirmed by nature nor 

 by the principle that the segments of the thorax are always in proportion to 

 the size of the locomotive organs which they respectively bear. 



G 2 



