282 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 112 



Figure 40 shows the accessary setae to be much longer than the 

 principal ones. It also shows the shape of the lamina before the 

 anterior apodeme. 



Tarsus III possesses only a very insignificant spine (fig. 41), the 

 existence of which one would deny if he were not prepared to find it. 



The pseudoculi (fig. 42) are extraordinarily large. The mouth parts 

 have not been examined, but must resemble those of wheeleri. 



Protentotnon transitans Ewing 



Figures 43-44 



Protcntomon transitans Ewing, 1921b, p. 196. — Ewing, 1940, p. 532. 



Ewing mentions only one specimen, the holotype, of this tiny 

 species, but in fact two more are present in his collection. Data for 

 the holotype are, Takoma Park, Maryland, in decaying leaves, H. E. 

 Ewing collector, April 24, 1921. Data for the other two specimens 

 are Jasper County, Georgia, in peach orchard soil, William F. Turner 

 collector, July 24, 1936. They were determined by Ewing as Protento- 

 mon and Proturentomon respectively, but the abdominal comb being 

 without teeth indicates that they belong to Protentotnon (see Tuxen 

 1956a). 



We have drawn the foretarsus from the exterior side and the ab- 

 dominal comb of the holotype (figs. 43-44) to show the likeness with 

 Protentomon perpusillum Berlese as described by Tuxen (1956a, 

 pp. 247-252) ; in fact there is no difference at all in these characters. 

 The only difference is found in the chaetotaxy, and it is very slight. 

 Tuxen (1956a) did not venture to decide whether Protentomon per- 

 pusillum Berlese and Protentomon thienemanni Strenzke were in fact 

 different species on account of the small chaetotactical differences. 

 The chaetotaxy of Protentomon transitans is in accordance with neither 

 of them. 



Thus the difference is stated schematically as follows: 



perpusillum thienemanni transitans 

 t VIII ant. 4 6 4 



t X 8 6 10 



s XI 4 6 6 



We should warn, however, against placing to much stress on these 

 differences in chaetotaxy. For instance, it is worth noticing that in 



Figures 41-49. — Eosentomon pusillum Ewing: 41, tarsus III, holotype; 42, shape of head, 

 holotype. Protentomon transitans Ewing: 43, foretarsus, exterior side, holotype; 44, 

 comb on abd. VIII, holotype. Acerentomon americanum Ewing: 45, foretarsus, exterior 

 side, holotype; 46, foretarsus, interior side, holotype; 47, tergum of abd. Ill, specimen 

 from Luray Caverns, Virginia; 48, sternum of abd. Ill, same specimen. 49, terga of 

 abd. VII-XII, same specimen. 



