Fnrther Observations on Koeuenia. 431 



Descriptioii of Plate. 



Plate 21. 



Fig. 1. Ventral surface of the first known stage {K. parvula) 

 of A'. ivheclerl. Camera drawing witli No. 8 ocular and 3 objective, 

 reduced one half. The ttree sternal cephalothoracic hairs are shown in their 

 normal position. The abdomen shows the bifurcated lung-sacs, on segments 

 two and three, thrown out on treatment with KOH. 



Fig. 2. Ventral surface of the abdomen of the second known 

 stage of K. icJicelcri. Drawn on the same scale and with earae reduction 

 as Fig. 1. The lung-sacs are absent on segments two and three, which now 

 possess very rudimentary repx'oductive appendages. Segments four and 

 five at this stage possess the paired lung-sacs over each of which project 

 three setae. 



Fig. 3. Ventral surface of the abdomen of the third and last 

 stage in the development of the naale of K. ivheeleri before the adult is 

 reached. Drawing on the same scale and with the same reduction as 

 Fig. l and Fig. 2. The lung-sacs now appear on all three of the ab- 

 dominal segments as is the condition in the adult. Only one pair of the 

 long hairs is present on the ventral surface between the lung-sacs of seg- 

 ments four and five. Segments two and three show prominent reproductive 

 appendages with a great incx'ease in the number of setae. 



Fig. 4. Ventral surface of the abdomen of the third and last 

 stage in the development of the female of K. ivheeleri before the adult 

 is reached. Drawn on the same scale and with the same reduction as the 

 preceeding figures. The abdomen presents the same appearance, beyond 

 the second segment as in Fig. 3 except that the ventral hairs between 

 the lung-sacs are shorter. The reproductive appendages of segments three 

 are quite similar , while segment two in this figure shows an appendage 

 much like the female of K, ivheeleri. Fig. 4 was not as much flattened 

 through pressure as Fig. 3, which gives it a narrower appearance. 

 Zool. Jahrb. XVIII. Abth. f. Syst. 29 



