J^24 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 108 



On the ventral surface of the body a pair of feathered setae is 

 found between coxae I. These are the first or anterior sternal 

 setae. The second or posterior sternal setae are located between 

 coxae III. With one exception there is one pair of second sternals ; 

 in one species there are four second sternals. All sternals curve 

 posteriorly and have relatively long and slender setules on the 

 outer curvature. Posterior to coxae III the number of ventral 

 setae varies with species and specimen. The arrangement into 

 rows is indistinct in most species, and ordinarily no elTort is made 

 to count these setae by rows. A ventral setal formula consists of 

 enumerating the first sternals and the second sternals plus the 

 total number of setae posterior to the sternals. However, since 

 the number of sternals is so constant in a species that deviations 

 are considered anomalous, ventral formulae usually are not given 

 in the descriptions. The number of sternals common to the species 

 and the range of variation of the setae posterior to the sternals 

 is given. All poststernal setae may be similar to the dorsals; or 

 there may be a rather sharp change in form about the level of the 

 anus. In the latter case the setae posterior to the anus have the 

 form of the dorsals; and those anterior to the anus have a dif- 

 ferent form. Ventral setae lie somewhat parallel to the body and 

 tend to be nude on the side adjacent to the body. 



In the descriptions of the species and groups of species a gen- 

 eral description will not be repeated. Attention will be concen- 

 trated on those features which at this time appear to be important 

 in making combinations of species or in differentiating them. In 

 plates 9-21, the appendages and their segments are referred to 

 by numbers. The order of the appendages and their parts are 

 the same as has been followed in this general description of the 

 morphology of the genus. All measurements are in microns. 



Diagnosis 



The diagnosis of Euschongastia by Fuller (1952), after emen- 

 dation, has been adopted for this paper : All legs with seven seg- 

 ments; true stigmata and tracheae absent; empodium clawlike; 

 no caudal plate ; eyes usually present ; coxa II with a single seta ; 

 scutum with five setae in addition to sensiilae; scutum not sub- 

 merged beneath the cuticular striae; sensiilae expanded distally; 

 chelicerae bladelike, each with a single dorsal tooth ; palpal claw 

 with two to seven prongs. 



A note should be added to this diagnosis. In the closely related 

 genus Neoschongastia the scutum is submerged beneath the cutic- 

 ular striae. In a few species of Euschongastia cuticular striae 



