SIPHONAPTERA 881 



Suborder FRACTICIPITA 



The Broken-headed Fleas 



In the members of this suborder the head is divided into two 

 distinct parts with a somewhat flexible articulation between them. 

 On the dorsal wall of the head the anterior part, the frons, overlaps 

 the posterior part, the occiput (Fig. 1124). 



Representatives of two subfamilies of this suborder occur in our 

 fauna; these families can be separated as follows. 



A. Ctenidia of the head consisting only of two broad teeth on each side in front of 

 the maxillary palpi, none between the palpi and the antennal groove; apex of 

 maxillae truncate, p. 881 IsCHNOPSYLLiDyE 



AA. Genal ctenidia, when present, placed between the maxillary palpi and the 

 antennal grooves or extending from the antennal groove to the anterior margin 

 of the head; apex of maxillae pointed, p. 881 Leptopsyllid^e 



Family ISCHNOPSYLLID^ 



This family includes those Fracticipita in which the ctenidia of 

 the head consist only of two broad teeth on each side close to the 

 lower anterior angle of the head, in front of the maxillary palpi, 

 (Fig. 1 1 24), and in which the apex of the maxillae is tiiincate. It is 

 represented in our fauna by only a few described species ; these infest 

 bats and are occasionally found on mice of the genus Peromyscus. 



Family LEPTOPSYLLID^ 



To this family belong most of our members of the suborder Fracti- 

 cipita. In these the genal ctenidia, when present, are placed between 

 the maxillary palpi and the antennal grooves or extend from the 

 antennal groove to the anterior margin of the head ; the apex of the 

 maxillae is pointed. 



Many Amerian species have been described; the greater number 

 of these infest rodents, a few species are found on birds, and some of 

 those infesting rats will attack man. 



Suborder INTEGRICIPITA 



The Unbroken-headed Fleas 



In the members of this suborder the head is not divided into 

 two distinct parts by an articulation, although a vestige of the seg- 

 mentation, the falx, may be present (Fig. 1122,/). The frons does not 

 overlap the occiput on the dorsal wall of the head. 



Representatives of three families of this suborder occur in our 

 fauna, these families can be separated as follows. 



A. Abdomen with small, sharply pointed spines on apices of tergites; inner 

 surface of anterior portion of hind coxee without small spines, although a 

 patch of bristles is sometimes present, p. 882 Ceratophyllid<e 



