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PR0GEEDIN08 OF THE NATIONAL MUSEUM. 



VOL. 39. 



Berlese's interpretations of the other parts (I and n) appear purely 

 fanciful to the writer of this paper. 



Cervical sclerites are of unusual occurrence in the Hymenoptera. 

 A small chitinous piece occurs on each side of the neck in the honey 

 bee (63, i) just below the anterior knob of the proepisternum (EpSj). 

 The ventral plate in the neck of Scolia duhia (fig. 17 B, Z) appears to 

 be a cervical sclerite rather than a prothoracic sternite. In Dolerus 

 aprilis there is a small dorsal cervical (13, g). Crampton (1909), 

 from a study of Dolerus, concludes that the plate called the proepi- 

 sternum (E'pSi) in this paper is really in large part a lateral cervical 

 sclerite. In Dolerus aprilis (13) it presents a small posterior subdi- 

 vision {eps^ just in front of the pleural suture {PS) which separates 

 it from the small epimerum (Epnij). This small piece (ejJSi) alone 

 Crampton thinks is the true prothoracic episternum, the larger ante- 

 rior part (EpSi) being a lateral cervical sclerite. The slender sclerite 



Fig. 17.— Propectus of Scolia dubia; A, lateral view; B, ventral view: Ciu procoxa; £pmi, epi- 

 merum; EpmA, epimeral arm; Eps\, episternum; j, ridge on side of episternum where edge of 



PRONOTUM OVERLAPS IT; I, VENTRAL CERVICAL SCLERITE; n, VENTRAL SUBDIVISION OF EPISTERNUM; PS, 

 PLEURAL suture; <Si, PROSTERNUM. 



(/) along the upper edge of the latter he regards as a dorsal cervical. 

 Hence, in all other forms he terms the large latero-ventral protho- 

 racic plate, where it is not subdivided into two parts {Eps^ and 

 eps^, the ''cervico-propleuron." While Dolerus may not be a 

 unique example of the subdivision of the lateral propectal plate, it 

 is certainly exceptional, and, to the writer of this paper, the structure 

 of one genus does not seem a sufficient basis for so wide a generaliza- 

 tion. The corresponding parts in Arge (12) certainly look much 

 more primitive than those of Dolerus (13), and the plates {EpSi and 

 Eprrij) on opposite sides of the pleural suture (PS) certainly here 

 suggest that they are the episternum and the epimerum of the pro- 

 thorax and nothing more. It is, then, simply a question of conden- 

 sation versus differentiation. Is Dolerus primitive and have the 

 simpler forms been produced by a complete fusion of the original 

 parts, or is Arge primitive and has Dolerus secondarily acquired its 



