xxxiii. '22] ENTOMOLOGICAL NEWS 273 



this sclerite, it seems advisable to designate the various feat- 

 ures in order to make clear the terms used in descriptions. 

 The dorsal surface of the prothorax is divided into three main 

 regions by two oblique, converging sulci, extending from the 

 basal to apical margins and dividing the surface into a central 

 discal area, with two bordering lateral areas of which the discal 

 a'-ea is the largest. The sulci which produce this division are 

 called the oblique sulci. The discal area is convex and highest 

 along its central portion, sloping gradually toward the apex 

 and also toward the sulci before reaching which it begins to 

 curve upward to a carinate edge forming the inner border of 

 the oblique sulcus. The depression which parallels this sulcus 

 and is a part of the discal area, is, in all of the species I have 

 examined, smooth, shining and impunctate, while the raised 

 portion of the discal area may be variously punctured and 

 hairy ; I shall call this depressed portion of the discal area the 

 oblique depression. The lateral areas lying between the oblique 

 sulcus and the lateral margin, are various in shape and in all 

 cases are extended further cephalad than the discal area. The 

 inner margin of these lateral areas is carinate and forms the 

 outer border of the oblique sulcus. Each lateral area is 

 divided near its basal third by a transverse sulcus which may 

 vary in shape and depth in the various species. The portion 

 of the lateral area cephalad of the transverse sulcus is gen- 

 erally punctate with varying hairiness and is inclined to 

 rugosity, while the smaller portion caudad of the sulcus gen- 

 erally has its inner surface at least, smooth and shining. The 

 surface of this division is, as a rule, convex and blister-like in 

 shape; T shall therefore speak of it as the bulla. It is about 

 this bulla that the ants seem to center their attentions and it 

 seems probable that here is the chief seat of glandular secretion. 

 The divisions <>f the prothorax above mentioned are to be 

 foind in all of our species at present described but in Hetaeriiis 

 ferrugmeus, the type of the genus, neither the oblique nor 

 transverse sulci are present. The oblique sulcus is indicate'! 

 by two parallel raised lines but there is no sulcus between them. 

 Of the transverse sulcus there is not the slightest indication, 

 neither is there any development of the bulla. In all other 



