74 Trans. Acad. Sci. of St. Louis. 



stigmatic organ with long, narrow pedicel and large clavate head, the 

 anterior margin of which is strongly pectinate. 



Abdomen almost twice as long as broad. Pteromorphse small, trun- 

 cate anteriorly and not projecting beyond the anterior margin of the 

 abdomen, attached to the anterior half of the same. Genital covers 

 smaller than the anal covers and situated a little over their length in 

 front of the latter. Abdomen hairless. 



Tarsus and tibia of leg I subequal; tarsus well clothed with hairs; 

 tibia sparsely clothed with hairs but possessing a large tactile hair aris- 

 ing from a small tubercle at the distal, lateral aspect. Claws of tarsus 

 monodactyle. 



Length, 0.44 mm.; breadth, 0.26 mm. 



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



Tyroglyphidae. 



Body soft; without tracheae; legs supported Tjy rod-like epimera; palpi 

 of three segments; eyes v/anting; legs arranged into two groups and 

 ending in claws, tarsi of legs I and II with a specialized clavate hair. 

 Young frequently passing through a migratory stage, known as the 

 hypopial stage in which they attach themselves to insects by means of 

 a number of disc-like suckers on the ventral surface of the body. 



Tyroglyphus Latreille. 



Mandibles chelate; cephalothorax and abdomen divided by a suture; 

 cephalothorax with four large posterior bristles; integument not granu- 

 lar; ventral apertures small; male with anal suckers; tarsi rather slen- 

 der, provided with distinct claws, and in some species with spines. 



One species. 



Tyroglyplius magnisetosiis n. sp. 



PL XI. f. 38. 



Brownish grey; legs lighter than the body. 



Cephalothorax broad, three-fourths as long as the abdomen. Anterior 

 pair of bristles slightly curved, almost one-half as long as the posterior 

 bristles; posterior bristles subequal, fully as long as the abdomen. 



Abdomen oval, two-thirds as broad as long and bearing about tv/enty 

 large, long, almost straight, simple bristles, the longest of which aro 

 fully as long as the entire body. The bristles of the abdomen are dis- 

 tributed as follows — a transverse row of six bristles situated near the 

 anterior margin, the two outer of these bristles being much smaller than 

 the rest; a transverse row of four large, subequal bristles situated near 

 the middle of the body; a group of eight bristles situated at the posterior 

 end of the abdomen. 



Legs moderate; anterior pair about as long as the abdomen. Tarsus 

 of leg I twice as long as the tibia; sense hair situated its length from 

 the posterior margin of the tarsus; tarsus without stout spines, but pos- 



