PROC. ENT. SOC. WASH., VOL. 23, NO. 9, DEC., 1921 195 



head. Exposed part of prothorax about two-thirds as long as broad. Meso-, 

 and metathorax subequal; their stigmata small and lateral. Abdomen very 

 whitish in front becoming more yellowish toward the tip; tergal apodemes not 

 thickened toward the middle, not antero-posteriorly arched and not branched 

 laterally; seventh abdominal segment slightly longer and slightly broader than 

 eighth. Legs moderate; anterior pair extending beyond the tip of head by the 

 full length of the tarsi and by about one-half the length of the tibiae, claws 

 about as long as those on other legs but not so strongly or evenly curved. Total 

 length, maximum extension, 1.14 mm.; width, 0.13 mm. 



Type. Cat. No. 24,579 U. S. N. M. 



Described from a single female which was one of many speci- 

 mens taken at Takoma Park, Maryland, from among decaying 

 leaves. This species is very much smaller than E. wheeleri 

 Silvestri, the only American species known in the past, and E. 

 vermiforme just described. The species appears to be common 

 in the smaller and finer-fibered leaves of decaying masses at 

 Takoma Park. 



Eosentomon minimum, n. sp. 



A minute, yellowish species. Head long, being nearly twice as long as broad; 

 pseudoculi either rudimentary or wanting; rostrum present, almost as broad as 

 long. Prothorax as usual. Meso-, and metathorax subequal; spiracles, large, 

 conspicuous and entirely lateral. Tergal plates of abdomen well developed and 

 equally conspicuous on all the segments; tergal apodemes conspicuous, very 

 slightly thickened toward the middle, not antero- posteriorly arched and not 

 branched laterally; seventh and eighth abdominal segments similarly shaped, 

 but the seventh is slightly the larger. Claws of anterior legs considerably 

 longer and stouter than those on the other legs. Length with segments some- 

 what telescoped, 0.54 mm.; width, 0.12 mm. 



Type. Cat. No. 24,580 U. S. N. M. 



Described from the type specimen, a male, taken at Takoma 

 Park, Maryland, from decaying leaves. This species is closely 

 related to palHdum but differs from it in several particulars, 

 especially in having the more anterior segments of the abdomen 

 as well chitinized as the posterior ones and in having a much 

 longer head. It is rare at the locality where taken. 



Protentomon, n. gen. 



Tracheae and spiracles wanting. First and second abdominal appendages 

 large, conspicuous and two-segmented; third abdominal appendages much 

 smaller, one-segmented. Apodemes wanting. A single transverse row of 

 dorsal setae on each abdominal segment. 



Type. Protentomon transitans Ewing. 



This species, which is here to be described and which is made 

 the type of this new genus, is by far the most important taxo- 

 nomicallv of anv of the American forms thus tar discovered. 



