SARCOPSYLLA 



Muridae and the common mouse is M. musculus. 

 Rodentia of the class Mammalia. 



297 

 They belong to the order of 



Sarcopsyllinae. 



Belonging to the subfamily Sarcopsyllinae, the Sarcopsylla penetrans (Derma- 

 tophilus penetrans) is of great importance in tropical countries. It is known as 

 the chigoe, nigua, or jigger. The male and virgin female are unimportant 

 as they do not penetrate^ the skin but act as ordinary fleas. The female, which 

 when unimpregnated is only about 1/24 of an inch long, when' impregnated 

 bores its way into the skin of man, especially about the toes," soles of the 



FIG. 82. Fleas, bedbugs and ticks. A, Lcemopsylla cheopis; B, P. irritans; 

 C, Ctenopsylla musculi; D, bedbug; E, cross section of rostrum of Ornithodorus; 

 F. longitudinal section of Ornithodorus. 



feet or finger-nails, and in the chosen site develops enormously, becoming 

 as large as a small pea. This enlargement takes place in the second and 

 third abdominal segments and is packed with eggs measuring about 400 microns 

 long and numbering about 100. A small black spot in the center of a tense rather 

 pale area is characteristic. The metamorphosis is similar to that of the flea. Sar- 

 copsylla can be differentiated from the flea by the proportionately larger head to 

 the body, and especially by the fact that the head is the shape of the head of a fish, 

 distinctly pointed. With the fleas the lower border of the head comes out in a 

 straight line to join the curve of the upper part. In the Sarcopsylla lower and upper 

 border of head are both curved. 



