Springtails: (Collembola) of the St, Louis Area 
last two segments annulate and covered with many small setae, 
third segment about 15 times longer than the fourth, first two 
Segments often heavily chitinized, last two segments less chit- 
inized ; post antennal organ somewhat triangular; eyes*not very 
conspicuous.due to. the scales and the heavily chitinized surfaces, 
but apparently ‘six are present; abdominal segments distinctly 
Separated, fourth segment’ shorter than the third; unguis with 
3 teeth, unguiculus lanceolate, one club-shaped tenent hair pres- 
€nt on the posterior basal part of each foot; furcula reaching 
to or almost to the venttal tube; dentes without crenate edge 
and with many short setae; out of 16 specimens examined 10 
had two large proximal spines, 5 shorter intermediate spines, 
and. two large distal spines on each of the two dentes of the 
furcula and, therefore, would be of the variety, americanus 
Schétt ; 3 specimens have only one large proximal spine on 
each dentes, then 5 intermediate spines, and then the two large 
distal spines and are probably of the variety separatus Folsom ; 
three were without a large proximal spine; mucro with two or 
in some one large proximal teeth, 6-7 intermediate teeth, usually 
7, and 2 large distal teeth. 3 3 
This species is common in America and Europe and may be 
classified as cosmopolitan in distribution. Records: November 
7. 1937, Ranken: Missouri, (E..D. Bueker); Buder Park near 
Valley Park, Missouri, March 15, 1936, (Leslie Hubricht) ; 
Ranken, Missouri,..May 17, 1936;. Vinita Terrace, Missouri, 
November . 28, 1936:..Grimsby,. Missouri, November 22, 1936, 
(Leslie Hubricht); Ranken, Missouri, March 4, 1934, (E. P. 
Meiners) ; Ranken, Missouri, October 1936, (E. D, Bueker). 
Is species is probably the most common and most conspicuous 
of Collembola in the St. Louis County region and can be taken 
Mettohe anywhere and during the entire year under leaf mold. 
_ “Subfamily Isotominae Schaffer, 1896 
ie of 
__ Antennae’ four segmented and about equal to the length of 
the head. “The'third and fourth abdominal segments are sub- 
equal. Body never with scales. Ae 
