408 H. E. EWING. 



Fam. TROMBIDIID^E. 

 Palpi free, the last segment being transformed into a 

 thumb, the preceding segment ends in a stout claw. Body 

 without shields ; eyes present ; coxae not radiate but arranged 

 in two groups. Body thickly clothed with hairs, cephalo- 

 thorax much reduced in size ; mandibles chelate. 



Gen. MICROTROMBIDIUM Haller. 

 Palpi ending in two claws instead of one, as is the case of 

 the members of the other genus of the family. 



A single species. 



Microtrombidium nigrum n. sp. 

 (Plate XIV., Figs. 10, 11.) 



Body black, clothed with pectinate bristles ; legs and palpi red ; abdo- 

 men constricted at about one-third its length from the cephalo-thorax. 



Cephalothorax small, narrow ; two-thirds as broad as long; two eyes 

 on each side of cephalothorax, situated on a short stalk, common to 

 both. Hairs on cephalothorax fewer and longer than those on the 

 abdomen; median groove prominent. Mandibles one-half as long as 

 the palpi. Segment two of palpus almost as long as the mandibles; 

 segment three about three-fifths as broad as long; segmeut four end- 

 ing in in two black claws, the outer being much the larger. This 

 species has large thumbs, longer than segment four of the palpus and 

 slightly swollen. 



Abdomen almost as broad posteriorly as anteriorly ; strongly con- 

 stricted slightly in front of the middle ; no elevated area on the dorsal 

 part of the posterior region. 



Legs long; anterior pair as long as the entire body; tarsus of leg 

 one not swollen, as long as the penultimate segment ; penultimate seg- 

 ment equal to antepenultimate. All the legs are sparsely clothed with 

 hairs similar to those of the abdomen but somewhat longer. Claws 

 of tarsi large and rather slender; those of the first pair of legs about 

 one-half as long as those of the other legs. 



Length, 1.90 mm.; breadth, 1.12 mm. 



Under bark of a hickory tree. Collected by James Zetek at 

 Danville, 111. 



Fam. ORIBATID/E. 



Cephalothorax with a specialized seta on each side above, 

 arising from a large pore near the postetior margin. Integu- 

 ment hard, well chitinized. Abdomen with chitinous wing- 

 like expansions called pteromorphse. Mouth parts small, 

 often invisible from above. 



