L'()l Mr. Shuckard's Monograph of the Dorylidae, 



and in the anamolous limitation of the number of joints of the an- 

 tennae, they resemble Myrmecodes and the rest of the apterous 

 Thynnida', although in the latter there is one joint more to be seen 

 than in these, viz. eleven. This curtailment is never found in the 

 apterous Social Heterogyna, to which however the single calcar to 

 all the tibiae, and their wanting eyes, approximates them, and I have 

 before stated that in the armature of the apex of the abdomen they 

 much resemble Ponera. They thus partake of both groups, but 

 they have this peculiar to themselves amongst the apterous Hetero- 

 gyna, viz. the small development of the pro thorax, which cannot be 

 seen from above, and the large development of the mesothorax at the 

 expense of it ; now in the apterous individuals of both the adjacent 

 groups, the Social and Solitary Heterogyna, we find either a very 

 large development of the prothorax or an equal one of both pro- and 

 mesothorax ; and in their males either the three divisions are equal, 

 or the meta- and meso- are equal and more fully developed than the 

 prothorax ; but where the meso- and metathorax are unequal, it is 

 the latter which is most developed. In the male Dorylida? we also 

 find an enormously developed mesothorax, and the prothorax rarely 

 observable from above ; to these they are likewise closely linked by 

 the two-jointed palpi, the size and conspicuousness of the lateral 

 spiracles of the thorax and abdomen, as also by the insertion of the 

 antennae near the edge of the clypeus. To Labidus especially do they 

 appear connected, by the carinae of the face, the dilatation of the 

 base of the calcaria, the proportions of the labial and maxillary 

 palpi, and the form of the mandibles, the latter differing no more 

 than might be expected in the opposite sex. The slight constric- 

 tion of the segments of the abdomen appears also a connecting re- 

 semblance. If from the preceding argument it is admitted that 

 these apterous insects must belong to the Dorylida, and from 

 analogy we may infer that they are females, and when we know 

 that their country is America and the West Indies, and that none 

 but females have yet occurred, and when it is further considered 

 that there is a genus of the same family from the same country of 



Plesia of Jurine, the type of it being the Tiphia metadata, Fab. Besides 

 this I am acquainted with genuine males of these Plesics which closely 

 resemble their females, and are totally different in structure from the Elis 

 sexcincta, Fab., the type of his genus Elis, and which has been latterly 

 usually considered as the Myzine of Latreille. Were the females of this 

 genus Elis winged, as several species of the male occur in the South of 

 Europe, it would be strange that the female should not have been captured 

 ere this. Sidney Smith Sanders, Esq. has informed me that he finds se- 

 veral species of Scleroderma not uncommon in Greece, where also he has 

 found more than one species of the male Elis, and for one species of each 

 cf which I am indebted to him. 



