22 The Grasjjedosomatidse of North America. 



Antenna; remote at base, geuerally elongate, third and fifth joints longest, 

 eighth joint Avith four olfactory" cones. 



Mandibles with 8-12 pectinate lamellae, a molar tooth, a dentate lamella, 

 and a masticatory plate. The stipe has a distinct cardo ; exposed surface of 

 stipe (bucciil area) very large and prominent, convex, not areate. 



Gnathochilarium with stipes separate, cardo small; in front the two coni- 

 ferous processes common to Chilognaths. 



Mentum entire, trapeziform, large. 



Promentum evident, triangular, included between the bases of the lingual 

 laminse, or nearly obsolete. 



Lingual laminse rather long, distinct, anteriorly with or without a denticu- 

 late lobe, posteriorly separated by the iDromentum. 



Median lobe well -developed, with a longer or shorter usually tridentate 

 process on each side. 



First segment slightly longer, but otherwise smaller than the second. 



Segments laterally strongly, moderately or not all carinate ; the dorsal face 

 of each provided with six bristles, sometimes rudimentary and very minute, 

 more or less arranged in a transverse row; each bristle usually located upon a 

 smaller or larger tubercle; surface otherwise smooth or roughened with tuber- 

 cles not setigerous. 



Repugnatorial pores wanting. 



Pedigerous laminse all free ; pleura completely coalesced with scuta. 



First, second, fourth and antepenultimate segments each bearing one pair 

 of legs, the third and last two footless. 



Anal segment obtuse or broadly truncate, with two pupillse at apex, each 

 ending in a long, slender bristle. 



Legs seven-jointed, generally long, the third, fourth and last joints longest. 



In males any of the legs of the first eight segments are subject to more or 

 less modification. 



Genital opening of males in the coxae of the second pair of legs, as in Poly- 

 desmidse. 



Number of segments, 26, 28, or 30, in adults; in young 28, 26, 23, 19, 15, 

 12, younger stages unknown. 



Distribution: Europe, North America, Northern Asia and 

 Northern Africa. 



The scarcity of individuals of this family, the small size of the 

 animals, and the fact that few localities outside of Europe and 

 North America have been thoroughly searched, leave it entirely 

 probable that the above distribution will be extended to the 

 mountain regions of Central and South America and Asia. One 

 species is known from the mountains of Mexico. It is a signifi- 

 cant fact that not a single form has been reported from the tropi- 

 cal regions, and the writers are confidant, after repeated and care- 



