78 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 82 



determined very plainly from the position of the setae. The anal or 

 tenth segment is separated from the ninth by an obscure suture. It 

 consists chiefly of the four anal lobes. There is no difiference in the 

 structure of these lobes and also armations do not occur as in other 

 genera. 



THE SPIRACLES 



Nine pairs of spiracles are present, eight of which are situated on 

 the epipleurites of the first eight abdominal segments. The ninth 

 spiracle is on the same sclerite of the prothorax very close to the 

 mesothorax. 



THE THORACIC AND ABDOMINAL SETAE 



It was found that the setal arrangement is very constant from 

 specimen to specimen. The number of setae varies in the different seg- 

 ments. The smallest number of setae was found to be present in 

 the anal segment (2x2) and the eighth abdominal segment (2 x 11) ; 

 the greatest number was borne by the meso- and metathorax (2 x 22). 

 The number of setae in the dififerent segments is best explained by 



Table III. — Setae of thorax and abdomen, nomenclature. 



Used on the Used on the 



Nomenclature of Dr. Russo segments New nomenclature segments Fig. 36 



Setole tergali mediana I, II, III, ilc. *• 1,11,111, 



Setole protergali 1-8 (■ beta praescuti ^^ 



Setole posttergali I, II, III, 1-8^ f I II III 



Setole tergali-laterali i rSeta sciituli J ' ' 



Setole tergali 9 J \ j.o 



Setole epipleuri I, 1-8 ^ . j jj jjj 



Setole pleuri-sternali 9* ^Seta epipleuricum ... < ' ' ' 



Setole tergali-pleurali 11,111, J ' ^'^ 



c . * 11 ■ * I. n. III, ( 



Seta stcrnellans . . . . j ' ' f 



Setole tergali-pleurali II, III 



Setole ipopleurali I, 1-8 "1 ( I II III 



Setole pleurali-sternali 9^ >-Seta hvpopleuricum •■■!','„ , 



Setole epipleuri II, III J 11-91 



.Setole sternali-anteriori-externe. . I 



Setole sternali-posteriori-externe. . I 



Setole sternali-mediane I 



Setole ipopleurale IT, III . ww.„ .,.^ .. ^ 



Setole sternali-laterali IT, III '^ 



.Setole sternal! mediane II, III 



Setole stemali i-8 J t tt ttf 



Not investigated Seta stcrnalis J, JJ, 111, a 



1-9 



Setole anali 10 Seta analis 10 g 



* The two dorsal setae. 

 ^ The two ventral setae. 



table No. Ill and figure 36. It should only be mentioned that the 

 meso- and metathorax and also the abdominal segments one to seven 

 are alike. The prothorax, the eighth, ninth and tenth abdominal seg- 

 ments differ considerably. It also should be noted that the first ab- 

 dominal segment does not show any difference from the following 

 one, as shown in ChactoptcUus vcstitus Fuchs, according to Russo. 

 The nomenclature of Russo has been adopted to a great extent but 

 several changes have become necessary as illustrated in table III. 



