416 AUGUSTA EUCKER, 



labium. The outerraost of tliese hairs, sometimes biit not usiially, 

 Stands off by itself wliile tlie otlier five arise close together in a 

 line. These hairs are just half the length of the corresponding hairs 

 in Kocnenia mirahilis. 



6. The arrangenient of the three pairs of hairs on the ventral 

 surface of the fourtli and fifth segments of the abdomen is character- 

 istic and unvarying- in the adnlt of our species. These hairs are 

 usually much long:er in the males than in the females. They are 

 likewise longer and more slender than the hairs of the ventral 

 region of either the fonrth or fifth Segments of K. mirahilis. 



7. The four lateral sense organs, first correctly described by 

 Hansen, are characteristic of onr Texan species alone. That these 

 four hairs appear only in the adult may perhaps acconnt for the 

 fact that there is a retardation sometimes and only three put in 

 their appearance. This happened in the type specimen, whicli I 

 described in my former paper. It likewise happened in one specimen 

 which was sectioued. In this case the organ could only appear to 

 the most donbting Thomas as three circles pressed closely together. 

 Another specimen liad four hairs on one side and three on the other. 

 It is very difficult to count the lateral sensory organs and I have 

 not examined as many of the adult Koenenia for these variations 

 as I have for other characteristics which can be made out on speci- 

 mens without the use of KOH. That there are exceptions to the 

 usual number of hairs is evident from the three cases mentioned. 



8. The reproductive appendages were naturally left for the last 

 since the specific characters were taken up in the order in which 

 they appear ontogenetically, Eighteen specimens of each sex were 

 cleaned in potassium hydrate and these with many glycerine and 

 baisam preparations, together with fresh animals, were used in a 

 re-examiuation of these appendages. I had not before laid very 

 much stress on the exact number and arrangenient of the setae over 

 the region of the appendages since they were not so important as 

 the structure of the appendages themselves and were probably not 

 characteristic features, but to my surprise I found not a singie ex- 

 ception to the fixed number of the setae and their regulär arrange- 

 nient. With this knowledge and cognisauce of the fact from my 

 former experience that the appendages are extremely • difficult to 

 make out, especially when one has only a few specimens, I have 

 drawn these regions with the utmost care, believing that the drawings 

 will teil more than pages of text. In the male the appendages of 



