176 The Ohio Naturalist. [Vol. VII, No. 8, 



antennae upon a black patch with a narrow border of purple. 

 Body, ovate dorsally with a re-entering angle; dorsum dark pur- 

 ple to black with a pattern in pearly white essentiall}- as follows: 

 on anterior half of dorsum a median longitudional purplish 

 streak between two pearly streaks wdth dentate margins; be- 

 hind these a square purple spot bounded by pearly and bisected 

 by a short median, longitudional, pearly streak; on either side 

 two 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 wdth 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. marmoratiis, 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. 



