56 Trans. Acad. Sci. of St. Louis. 



2. Legs very long, hind pair at least twice as long as the body 3. 

 Legs much shorter, hind pair never one and a half times as long 



as the body 4. 



3. Thumbs enormously swollen, being much broader than segment four 



of the palpus R. pollicaris. 



Thumb moderately swollen, equal to segment four in width 



R. parvisetosus. 



4. Palpi twice as long as the mandibles 5. 

 Palpi subequal or but slightly longer than the mandibles 8. 



5. Tarsus of leg I longer than the tibia R. longitarsus. 

 Tarsus of leg I not longer than the tibia 6. 



6. Tarsus of tibia of leg I subequal in length R. erythreus. 

 Tarsus of leg I much shorter than the tibia 7. 



7. Tarsus of leg I not swollen R. quadrioculus. 

 Tarsus of leg I quite swollen R. hrevitarsus. 



8. Integument of body with many small black spots R. leprosus. 

 Integument of body without spots R. parvipollicus. 



Rhyiicliolophus tridcntifer n. sp. 



PI. VIII. f. 2-3. 



Light red; appendages much paler than the body. Body well clothed 

 with peculiar hairs or bristles. Each hair consists of three long prongs 

 united at the base in such a manner as to form a trident; prongs of the 

 trident equal, curved inward and pectinate on their outer margins. 



Cephalothorax much reduced, about as broad as long. Palpi about 

 one half as long as the anterior pair of legs; thumb small, not swollen, 

 extending to the tip of the palpal clav/; palpal claw about as long as the 

 segment from which it extends, slightly curved; second segment of the 

 palpus the largest, about one-half as broad as long. Mandibles tv.'o- 

 thirds as long as the palpi. Dorsal groove extending the entire length 

 of the cephalothorax with a circular expansion at about one-third its 

 length from the posterior end; a long thread-like pair of hairs situated 

 on this circular expansion which are about one-half as long as the 

 groove itself. A single pair of eyes situated upon an oblong elevation 

 about half way between the dorsal groove and the lateral margin of 

 the cephalothorax. 



Abdomen long, swollen in front between the first and second group of 

 legs. 



Anterior pair of legs about two-thirds as long as the body; tarsus 

 longer and broader than the tibia; tibia and antepenultimate segment 

 subequal. Second and third pair of legs subequal; hind pair of legs 

 equal to the anterior pair and extending slightly beyond the posterior 

 margin of abdomen. Tarsus and tibia of the last pair of legs subequai. 

 All the legs well clothed with bristles. 



Length, 0.90 mm.; breadth, 0.48 mm. 



Common under the bark of soft maple trees and some- 

 times found under the bark of other trees. Collected by 

 J. D. Hood at Urbana, III, and by the writer at Areola and 

 Muncie, 111. 



