DERMATOPHILUS PENETRANS 



863 



on the pig's abdomen, and quickly another and another. These 

 black specks are jiggers, which can easily be transferred to a test- 

 tube. On examination, they will be found to be males and females 

 in about equal numbers. It appears likely that a number of different 

 species, if not genera, are included under the term D. penetrans, 

 and there is without doubt room for investigation into jiggers taken 

 from wild and domestic animals and man. 



If the reader will look at the list of synonyms, it will be clear 

 that, by the law of priority, the name of this httle insect should 

 be Rhynchoprion penetrans, and not D. penetrans, as the name 

 Rhynchoprion Oken is dated 181 5; but Rothschild has recently 

 pointed out that Rhynchoprion was apphed in 1804 by Hermann 

 to a tick, and also by'Oken to other ticks in 1815. 



Geographical Distribution.— It occurs in Mexico, West Indies, 

 Central and South America, through 

 the whole ot tropical Africa, and as J^r 

 far south as Mashona — i.e., 30° N. -j^^ 

 to 30° S. In Asia it does not appear ^^^^ 

 to flourish; it has only infected Bom- 



bay, and will probably not become -^^K^ /IT^X 



naturalized, as the monsoon conditions do not appear good for it, 

 lor it flourishes in a warm, dry, sandy soil. 



The female only becomes endoparasitic, and when it first arrives 

 in a place, and is unknown, may cripple people, and cause loss of one 

 or more toes. 



Morphology. — -The general account already given of the morpho- 

 logy of fleas and the special characters indicate the morphology 

 sufficiently for the purposes of this book. 



Life-History. — -The males and females live in dry, sandy soil as 

 reddish-brown little insects about i millimetre in length, and are 

 very active. They live by sucking the blood of warm-blooded 

 animals. When impregnated, the female burrows into the skin of 

 a warm-blooded animal, whether bird or mammal. The abdomen 

 now swells enormously into the size and appearance of a small 

 pea. If one of these small peas is examined, it will be seen to 

 show the head and thorax anteriorly, and the two last abdominal 



Fig. 455. — Dermatophilus penetrans: Fig. 456. — Devmatophilus penetrans . 



Pregnant Female. (After Newstead, Annals of Tropical 



Medicine and Parasitology.) 

 a, Larva; h, younger larva; 

 c, empty cuticles of eggs. 



