132 Journal New York Entomological Society. [Voi. xvii. 



Cephalothorax longer than broad and very much narrowed at the insertion of 

 the first pair of legs. Pseudostigma projecting ; pseudostigmatic organ clavate and 

 slightly recurved, a little over one half as long as the femur of leg II. There is 

 situated very near the pseudostigma on its inner side a very long, simple bristle, as 

 long as the cephalothorax itself. 



Abdomen rectangular, but the anterior, lateral and posterior margins are all 

 slightly convex. This species is peculiar and remarkable in possessing on its pos- 

 terior margin four long, stout, slightly curved, simple and subequal bristles, each 

 being almost as long as the width of the abdomen at its posterior margin. Ventral 

 plate long and narrow, deeply emarginate just opposite the anterior end of the anal 

 covers; genital covers when taken together are broader than long, situated approxi- 

 mate to anal covers; anal covers very long and narrow, aliout one sixth as broad as 

 long. , 



Legs stout ; leg I three fifths as long as the body. Tarsus of leg I but slightly 

 longer than the tibia ; tibia and genual subequal. Ungues stout, monodactyle. 



Length, 0.82 mm.; breadth, 0.38 mm. 



In trash. Collected by C. R. Crosby at Columbia, Mo. INIany 

 specimens. 



Genus HYPOCHTHONIUS C. L. Koch. 



Ventral plate anchylosed to dorsal plate ; without lamellae ; legs 

 stout ; abdomen with a transverse suture or sutures, as if segmented. 



This is the first new species of this rare genus to be discovered in 

 America. 



Hypochthonius crosbyi, new species. (Plate VI, Fig. ;i;i.) 



Alcoholic specimens light yellowish brown. 



Cephalothorax one and one half times as long as broad and three fifths as long 

 as abdomen. The cephalothorax bears dorsally two pairs of bristles, a small curved 

 pair at the tip of the rostrum and a larger, almost straight pair between the pseu- 

 dostigmata. Pseudostigma low, cylindrical ; pseudostigmatic organ long, flagelli- 

 form, simple, almost as long as the cephalothorax. Palpi prominent. 



Abdomen with two transverse sutures. The anterior suture is situated about one 

 fourth the length of the abdomen from the anterior margin of the same, while the 

 posterior, which is the longest, is situated almost in the middle of the abdomen. 

 Genital covers very large, triangular, about two thirds as long as the posterior 

 pair of legs and one third as long again as the anal covers ; anal covers long and 

 narrow, truncate anteriorly reaching from the genital covers to the posterior margin 

 of abdomen, inner margins concave, outer convex. 



Anterior pair of legs slightly longer than the cephalothorax. Tarsus of leg I 

 almost twice as long as tibia; tibia and genual equal. The tibia of leg I bears a 

 very long, tactile bristle, about as long as leg I itself. Ungues monodactyle. 



Length, 0.38 mm.; breadth, 0.22 mm. 



In trash. Collected by C. R. Crosby at Columbia, Mo. Several 

 specimens. 



