300 



HULLETTN 54, UNITED STATES NATIONAL MT^SETTM. 



Head ln-oader than loiio-; eyes situatod i)o,st-lat(M-!illy. First paii'of 

 antenna? with the first two peduncular joints hirge, the second half as 

 long- as the first; the third joint long- and slen- 

 der, twice as long as second joint; flageilum 

 consists of seven joints. The first two pedun- 

 cuhxr joints of the second pair of antenna' are 

 of equal length; the following three are of equal 

 length and longer than the first two; the flagei- 

 lum consists of about seven joints, and extends 

 to the posterior margin of the third thoracic 

 segment. 



The thoracic segments are of equal length, 

 with the exception of the first, which is slightly 

 longer. The seventh segment is produced back- 

 ward in two rounded lobes, one on either side 

 of the median line, and close together. 



The first abdominal segment has two suture lines at either side, 

 indicative of coalesced seomerits. The terminal segment is verv con- 



FlG. 319.— DYNAMENE per 



FORATA. Last two tho 



RACIC SEGMENTS ANT) AB 

 DOMEN. 



Fig. 320.— Dynamene perforata (After Moore), a, First antenna. 6, Second antenna, c, 

 Male. d. Tip of maxilla, r, Mandible. /, Maxillipeds. g, Fourth leg. h. First leg. i, 

 Seventh leg. ./, 1'art of terminal segment of abdomen with i'ropod. 



vex at the base, and has four small tubercles, forming a square on the 

 con\'exity. Its apex has a heaii-shaped ()p(Miing, foi-nuHl by the pro- 



