176 
The Ohio Naturalist. 
[Vol. VII, No. 8, 
antennae upon a black patch with a narrow border of purple. 
Body, ovate dorsallv with a re-entering angle; dorsum dark pur¬ 
ple to black with a pattern in pearly white essentially as follows: 
on anterior half of dorsum a median longitudional purplish 
streak between two pearly streaks with dentate margins; be¬ 
hind these a square purple spot bounded by pearly and bisected 
by a short median, longitudional, pearly streak; on either side 
tw r o short irregular pearly lobes extending obliquely forward; 
next behind on the median line are one to three roundish purple 
spots broadly surrounded by pearly white; on posterior abdomen 
a long, oblique, pearly bar directed forward from either side of 
the median line; abdomen with a small pale tubercle on either 
side of the middle; dorsum naked anteriorly with short white 
bristles posteriorly; anal tubercle with bristles four times as long 
and with a median longitudional purple bar; sides purple to 
blackish, with conspicuous, hazel, chestnut and cinnamon mot- 
tlings' thorax with a broad, lateral longitudional, pearly band, 
sometimes replaced by one to four bright white spots; sides of 
abdomen with two to five large conspicuous pure, white spots, 
widely separated; ventral surface lilac or lavender. Legs long, 
purple and yellow; tibia with broad alternate bands of dark violet 
and wax yellow; bristles white. Claws, white, superior claw 
long, tapering ,rather straight, six toothed; inner edge with two 
prominent teeth at about equal intervals, two more on both sides 
near the outer edge, dividing it into thirds; inferior claw half as 
long as the other, straight, tapering, bearing sub-apically a slen¬ 
der bristle longer than the claw; also a tooth upon a swelling on 
the inner edge near the base. Furcula almost reaching the head, 
manubrium, stout, purple; dentes twice as long, slender, pale 
lilac; each with a long, white bristle on either side and a single 
extra long ventral sub-apical bristle; mucrones, white, less than 
one-third the dentes, narrowly elliptical; ventral concavity shal¬ 
low with distinct serrate edges; apex clearly emarginate, having 
a median rounded, quadrate notch between two rounded teeth. 
Ventral sucker with filaments extensible to the length of the 
antennae. Length, maximum, 3.3 mm. Habits; reported 
by Folsom from a green house at Cambridge, Mass., upon wet 
decaying wood, and upon the outside of algae coated flower pots 
in shaded, moist situations. 
This species seems to be quite abundant, and closely resembles 
P. marmoratus , but differs from this species in the character of 
its claws, having six teeth on its superior claw, while marmoratus 
has but four. It is easily recognized by the broad white head 
band with sagittal mark, the three- median dorsal streaks, and 
the brilliant white spots on the sides of the abdomen. Types 
were deposited in the Museum of Comparative Zoology at 
Cambridge. 
