AMERICAN APTERA. 415 



posteriorly than anteriorly and situated one-half their length from the 

 posterior margin of ventral plate. Abdomen with a few fine hairs. 



Anterior pair of legs as long as abdomen ; tarsus slightly longer 

 than tibia ; genual two-thirds as long as tibia : femur almost three 

 times as long as genual. Tactile hair almost twice as long as tarsus. 

 Unguis tridactyle ; dactyles unequal. 

 Length, 0.37 mm. ; breadth, 0.24 mm. 



Under bark. Collected by the writer, Urbana, Illinois. 

 Manv specimens. 



Fam. NOTHRID^. 



With specialized seta arising from a pore on each side of 

 the dorsal surface of the cephalothorax near the posterior 

 margin. Abdomen immovably fused with cephalothorax and 

 without pteromorphae. Segments of legs often stout, some- 

 times swollen. 



Gen. NEOLIODES Berlese. 



Cephalothorax without lamellae ; legs short and stout ; 

 abdomen without transverse suture ; dorsum of abdomen con- 

 vex, and carrying nymphal skins showing concentric rings ; 

 unguis tridactyle. 

 One species. 



Neoliocles concentrica Say (?).* 

 (Plate XVI, Figs. 23, 24, 25, 26.) 



* I think it would hardly be possible for any one to determine this 

 species from Say's description in Jour. Phila. Acad., vol. ii, 1821, p. 

 73. Most of the characters given in this description are either generic 

 or are based upon erroneous ideas of the anatomy of the acarina, as 

 for example, his reference to the eyes as being " Two, minute, brown- 

 ish, elevated on an elongated, slender filiform peduncle." This refer- 

 ence is evidently to the pseudostigmatic organs. 



Since I found that my specimens did not agree with Banks' figure 

 of concentrica on page 72 of his treatise on the acarina, at first I thought 

 it was new. Recently I have found this species in Wisconsin and many 

 places in Illinois, always under bark. Mr. J. D. Hood has also sent 

 me specimens of it taken from under bark in Michigan. I would infer 

 from this that the species probably has a general distribution over the 

 United States, and since it has always been found under bark and is 

 the only common species of the genus found in this situation in this 

 country it likely is Say's species, for he found concentrica only under 

 bark. If it should prove in the future to be new, I would suggest 

 that it be named after Mr. Hood, who first found the species in the 

 middle part of the continent. 



TRANS. AM. ENT. SOC, XXXV. NOVEMBER, 1909. 



