144 



joint of all the legs there are 4 lateral spines and a subapical pair, and 

 between the third and fourth lateral spines there is a hair. 



Modified segments. (9) The eighth tergite has no hairs back of 

 the stigma. The apical margin is rounded at the apex and contains 

 8 or 10 bristles. The stylet is short and wide and contains at its tip 

 a long and a short bristle. 



. ( $ ) The manubrium is short and narrow. The movable finger of 

 the clasper is short, thick, swollen at its middle, bluntly rounded at 

 its extremity, and contains on its upper border numerous hairs and 

 a few on its lower border. 



Rothschild (9) has pointed out certain differences between the 

 Ctenocephalus canis and Ctenocephalus felis. The differences are that 

 in the female of the felis the head is longer and more pointed. This 

 , difference is not so pronounced in the male. Also certain differences 

 in the shape of the claspers and the number of bristles in the epister- 

 num and epimerum of the metathorax and the hind femur, those in 

 the C. canis being more numerous. Also that group of bristles on 

 the posterior border of the hind tibia between the fifth pair and the 

 apical bristles consists of two in the Ctenocephalus canis, while there is 

 but a single bristle with a small hair in the Ctenocephalus felis. 



REFERENCES. 



1. 1909, McCoy. "Plague Bacilli in Ectoparasites of Squirrels." Public Health 



Reports, Vol. XXIV, No. 16. 



2. 1908, Schumann. "A Disease of Rats Caused by Mites." Centralblatt f. Bact., 



Oct. 30th. 



3. 1909, McCoy and Mitzmain. "An Experimental Investigation of the Biting of 



Man by Fleas Taken from Rats and Squirrels." Public Health Reports, Vol. 

 XXIV, No. 8. 



4. 1908, McCoy. "A Report on Laboratory Work in Relation to the Examination of 



Rats for Plague at San Francisco, California." Public Health Reports, Vol. 

 XXIII, No. 30. 



5. Wagner. Aphanipterologische Studien aus dem zootomischen laboratorium der 



Universitat zu St. Petersburg. 



6. 1908, Mitzmain. "How a Hungry Flea Feeds." Entomological News, December. 



7. 1908, Miller. "Hepatazoon Perniciosum (N. G. N. SP.). A Hsemogregarine 



Pathogenic for White Rats; With a Description of the Sexual Cycle in the 

 Intermediate Host; A Mite (Laelaps Echidninus)." Bull. No. 46, Hyg. Lab. 

 U. S. Pub. Health and Mar. Hosp. Serv., Wash. 



8. 1908, Jordan and Rothschild. "Revision of Non-Combed Eyed Siphonaptera." 



Parasitology, Vol. I, No. 1. 



9. 1901, Rothschild. "Notes on Pulex canis, Curtis, and Pulex felis, Bouche." 



Entomologist's Record, Vol. XIII, No. 4. 



1905, Rothschild. "Some Further Notes on Pulex canis, Curtis, and Pulex felis, 

 Bouche." Novitates Zoologicae, Vol. XII. 



