98 
Psyche 
[September 
This species is very close to Tullhergia affinis Borner in the 
arrangement and size of the 3 anal horns, but differs in that pseud- 
ocelli were not observed on thorax I, the unguiculus was not dis- 
tinguished, the size is smaller, and there seems to be differences in 
the organ of the 3rd antennal segment and postantennal organ. 
Genus Onychiurus Gervais. 
Onychiurus wilchi, n. sp. 
(Figs. 18-25) 
Length up to 1.5 mm. White. Postantennal organ (Fig. 20) of 
the fimetarius type, each with 18-20 branched tubercles placed at 
right angles to the long axis. Antennae shorter than the head, with 
the antennal segments in the following proportions: 7:13:15:17. 
Organ of the third antennal segment (Fig. 19) with 5 papillae, 5 
guard setae, 2 sense rods, and 2 sense clubs. Fourth antennal seg- 
ment with 10-12 curving olfactory hairs. Pseudocelli (Fig. 18) on 
each side as follows: 2 on inner side of antennal base and one be- 
tween antennal base and postantennal organ ; 2 obliquely situated 
on back of head; meso- and meta-thorax 2; 2nd and 3rd abdominal 
2; 4th and 5th abdominal 3. One pseudocellus on each precoxal. 
Unguis (Fig. 21) stout, curving, unarmed. Unguiculus unarmed, 
slender, gradually tapering to apex which is extended in the form of 
a fine filament to length of unguis. Anal spines 2 (Fig. 23), stout, 
and almost straight, bases widely separated; two-thirds as long as 
hind unguis. Long curving setae at posterior end of abdomen. Cloth- 
ing of scattered long straight setae, sparse short setae, and a few 
minute strongly curved setae (Fig. 24). Cuticular tubercles (Fig. 
23) coarse. 
Highland, Illinois June 7, 1946, B. T. Wilch. This species is 
named for Mr. B. T. Wilch who collected fifteen specimens from 
garden soil, and which were transmitted to me for study by Dr. 
H. H. Ross, of the Illinois Natural History Survey, with whom 
most of the cotypes will be deposited. 
Genus Xenyllodes Axelson, 1903. 
Eyes 5 on each side of head. Postantennal organ consisting of 
a single, trilobed tubercle. Antennae with broad basal segments. 
