422 



BULLETIN o4, UNITED STATES NATIONAL MUSEUM. 



ASELLUS INTERMEDIUS Forbes. 



Asellus mtermed'ms Forbes, Bull. 111. Museum of Nat. Hist., No. 1, 1876, pp. 

 10-11.— Underwood, Bull. 111. State Lab. Nat. Hist., II, 1886, p. :-]58.— 

 Richardson, American Naturalist, XXXIV, 1900, p. 297. 



Localities. — Found in hill countiy of southern Illinois, under stones 

 in small streams. 



Bod}' oblong'-ovate, about three times as long as wide, 2 mm.: 7 mm. 

 Head wider than long, 1 nun.: li mm., with the anterior margin 

 straight. Sides of head entire, with a small 

 lol)e on either side near the base. Eyes small, 

 composite, and situated close to the lateral mar- 

 gins, halfwa}" between the anterior and the 

 posterior margins. The first pair of antennae 

 luive the basal article large and somewhat di- 

 lated; the second article is half as wide as the 

 tirst and about as long; the third article is a 

 little more than half as long as the second. The 

 tiagellum is composed of nine articles and ex- 

 tends to the middle of the fifth article of the 

 peduncle of the second pair of antenna. The 

 second antennae hav^e the first three articles 

 short and about equal in length; the fourth arti- 

 cle is about as long as the tirst three taken 

 together; the fifth is one and a half times longer 

 than the fourth. The fiagellum is composed of 

 about fifty articles and extends a short distance 

 beyond the posterior margin of the seventh thoracic segment. The 

 maxilliped has a palp of five articles. The palp of the mandibles is 

 composed of three articles. 



The first segment of the thorax 

 has the lateral margins entire, 

 with the anterior angle not devel- 

 oped and the epimeral lobe" large 

 and conspicuous and placed an- 

 tero-laterally. The second, third, 

 and fourth segments have the 

 lateral margins entire, with the 

 antero-lateral angles well devel- 

 oped, and the epimera small and 

 almost inconspicuous and placed 



antero-laterally. The fifth segment has the anterior part of the lat- 

 eral margin produced in a well-defined lobe, with the epimeron large 

 and conspicuous and placed about the middle of the lateral margin, 



Fig. 47-1.— Aselia's interme 

 Dirs. -. 7. 



.\SELLUS INTERxMEDH'S. ((, FlKST LEG. 



/i, Abdomen with urfoiw. ■'Us. 



