142 



PULEX IRRITANS Linnaeus. 

 [Plate V.] 



Head. Evenly and abruptly rounded in both sexes. Frontal 

 notch absent. Eye large. Maxillary palpi longer than the labial 

 palpi. Labial palpi reach to about half the length of the anterior 

 coxa and are 4-jointed. The mandibles are broad and markedly 

 serrate. Maxillae triangular. Antennal groove short and wide, 

 closed behind, thickened on edges, and reaches to top of head in both 

 sexes by chitinous thickening. Second joint contains 8 or 9 fine hairs, 

 shorter than the third joint. Division of the third joint only to be 

 seen on dorsal surface. Two bristles on the gena, one placed low 

 down just above the maxilla, the other below the eye. From the 

 lower margin of the gena occasionally may be seen a small tooth. 

 One bristle on the occiput near the posterior lower angle. A few fine 

 hairs on the posterior edge of the antennal groove. 



Thorax. The thoracic nota each contain a single row of about 10 

 or 12 bristles. There is no ctenidium on the pronotum. The meso- 

 sternite is narrow and is not divided by an internal incrassation. The 

 episternum of the metathorax is large and contains about 2 or 3 

 bristles and is not quite separated from the sternum anteriorly. The 

 epimerum has an anterior row of about 7 or 8 bristles and an apical 

 row of about 6. 



Abdomen. Each of the abdominal tergites, with the exception of 

 the first, has a single row of 8 or 10 bristles. The first has 2 rows of 

 about 4 each. The sternites from third to seventh have a single row 

 of about 6 bristles. There is one short antipygidial bristle on each 

 side. 



Legs. The hind coxa has on its inner surface posteriorly a number 

 of fine hairs, while anteriorly there are 10 or 12 teeth in an irregular 

 line. The hind femur has on its inner surface a row of about 8 or 9 

 bristles. The spines on the posterior tibia are in pairs, and there are 

 about 7 bristles in a line on its outer lateral surface. The apical 

 bristle of the second tarsal joint of the hind leg reaches to about the 

 middle of the fifth joint. The last tarsal joints of all the legs contain 

 4 lateral spines and a subapical pair, and between the third and last 

 lateral spine there is a hair. 



Modified segments. ( 9 ) The eighth tergite has no bristles above 

 the pygidium but has numerous short stout bristles laterally and on 

 and close to the apical margin. The stylet is short and stout and 

 has at its tip a long hair. The tenth sternite and tergite contain 

 numerous fine hairs, those on the sternite confined to the apical edge. 



( <?) The male claspers are quite characteristic. The manubrium 

 is large and curved and points ventrally. The claspers have two 

 processes, the lower of which, with the finger, form together a kind 



