378 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xxvii. 



Genus PULEX Linnaeus. 



1758. Pulex LiNN^us, Systema Natura*, 10th ed., I, p. 614. 



1840. Pulex Westwood, Introd. to Mod. Classif. of Ins., II, Gen. Synoj)., p. 124. 



18-57. ? MonopsyUus Kolexati, Wiener En torn. Monats., I, p. 65. 



1863. Pulex and Trichopsyllus Kolenati, Horye Soc. Ent. Eoss., II, p. 29. 



1898. Pulex Wagner, Horse Soc. Ent. Eoss., XXXI, p. 21. 



Though h'r items is the type of this genus, still we have included 

 three species possessing pronotal ctenidia. In one of these, however, 

 the number of spines is unusually reduced, showing a transition in 

 this respect toward irritans- 



SYNOPSIS OF AMEEICAN SPECIES. 



a. Prothorax without ctenidial spines. 



h. Abdominal tergites with but one distinct transverse row of liristles, and \\ithout 

 minute teeth; inner side of hind coxa distally with an obhque row of minute 

 teeth; vertex without transverse rows of bristles; hind margin of antennal 

 groove with a few weak hairs. 

 c. Teeth on inner side of hind coxa numerous" and in an irregular row; labial 

 palpi apparently 3-jointed; fifth tarsal joint without minute hairs on disk. 

 d. Labial palpi extending about one-half the length of anterior coxae. 



irritans (p. 379). 

 dd. Labial palpi extending three-fourths the length of anterior coxse or 



more dugesii (p. 379). 



ce. Teeth on inner side of hind coxae six in number and in a regular row; labial 

 palj^i as long or longer than the anterior coxae, and apparently 4-jointed; 



fifth tarsal joint with minute hairs on disk brasiliensis (p. 379). 



bb. Abdominal tergites with two distinct rows of bristles; hind margin of metano- 



tum, and tirst, second, and third tergites with small teeth; inner side of hind 



coxae without minute teeth; vertex with two transverse rows of bristles; hind 



margin of antennal groove with a close-set row of numerous minute teeth. 



c. Abdominal tergites -all with a second row of numerous small bristles; hind 



margin of antennal groove with about a dozen minute teeth ; maxillary palpi 



with second and fourth joints nearly equal and longer than the first, which 



is longer than the third ; first three abdominal tergites with minute teeth, the 



first with about 11 on each side, the last with about three on each side; hind 



tibife with spineson liind margin short and weak and with many short 



bristles on the outer side in several longitudinal rows bohlsii (p. 380). 



cc. Abdominal tergites without a distinct second row of bristles excepting on first 

 two, the remainder with but one or two bristles on each side in place of 

 second row; hind margin of antennal groove with a thick-set row of about 

 25 minute but well-developed teeth; maxillary palpi with first and third 

 joints nearly equal and second longer than fourth; first abdominal tergite 

 only with minute teeth; hind tibi;« with long, strong spines on the hind 



margin and about eight stout bristles on the outer side luizii (p. §80) . 



aa. Prothorax with a ctenidium. 



b. Pronotal ctenidium with about 9 spines anomalus (p. 381). 



bb. Pronotal ctenidium with about 17 spines. 

 c. Vestiture of spines and bristles rather heavy ; a spine on hind distal angle of 

 second joint of hind tarsi as long as joints 3 and 4 and three-fourths of 5 

 together; upper male claspers short and stout, lower claspers shaggy, with 



hairs affinis (p. 382) . 



cc. Vestiture comparatively light; a spine on hind distal angle of second joint of 

 hind tarsi as long as joints 3 and 4 and scarcely one-fourth of 5, together; 

 upper male claspers long and slender, lower claspers with few hairs. 



lynx {i>. 383) . 



