78 



persons working in the old laboratory, where numerous animals 

 were kept and where large numbers of rats were sent for examina- 

 tion for plague infection; these fleas proved to be Pulex irritans 

 and Pulex serraticeps. The flea occurring on rats in Manila was 

 never found on human beings. 



I am indebted to Mr. W. Schultze, assistant entomologist of this 

 Laboratory, for the greater part of the following description of the 

 flea found on rats in Manila: 



Pulex pMlippinensis, sp. nov., Manila, July 19, 1904. 



Head, with very small bristles; front of head high and rounded. 

 Eyes round. Above the latter and directed backward are the 

 antennae, which are club shaped and consist of three segments. 

 First and third segments equal in size; the third segment cup 

 shaped; the second segment very small. Superior maxilla elon- 

 gated, triangular. Palpi maxillarum consist of four segments, of 

 which the last is the longest. The posterior margins of the 

 thoracic segments possess each a row of flne bristles, as do also 

 the abdominal ones. On the latter the bristles extend from the 

 back downward to the middle of the abdomen, and from below 

 upward. On the back, on the posterior margin of the eighth abdom- 

 inal segment are two large bristles. In the male, below the 

 external genitals, two large bristles on each side— i. e., four in all. 

 Abdomen of the male bent upward. In the interior of its abdomen 

 are the spinally curved internal sexual organs, more or less distinct 

 in different individuals. The abdomen of the female is oval and 

 egg shaped. Bristle on the ninth segment around the external 

 genitals. In the abdomen of the female between the seventh and 

 the eighth segment is an intestine or sausage-like curved organ — the 

 ovary. Behind it in one individual are several barrel-shaped ova. 



The longest bristles are found at the lower ends of the femora. 

 They measure 0.2 millimeter in the female and 0.15 millimeter in 

 the male: 



Color: Light reddish-brown. 



Size of the female: Length, 1.8 to 2.67 millimeters; breadth, 

 0.80 to 1.25 millimeters. 



Size of the male: Length, 1.16 to 1.78 millimeters; breadth, 

 0.70 to 0.75 millimeter. 



Size of the ova: Length, 70 /x; breadth, 55 fx. 



Types in the collection of the entomological division of the 



