274 PARASITES OF MAN 



as does also the wound inflicted by the water-boatman 

 (Notonecta glauca). There are other species of bug, such as 

 the Acanthia rotundata of Reunion Island and A. ciliata of 

 Kasan, the bites of which are worse than that of the common 

 species. The fly -bugs also, such as the Reduvius persona tus, so 

 common in France, and the R. amcenus of Borneo and Java, 

 attack man, although their especial habit is to attack and destroy 

 other insects, including bugs themselves. Other species or 

 varieties of Reduvius (R. cruentus, and R. serratus) attack man. 

 The last named is an Indian form, capable, it is said, of pro- 

 ducing an electric shock. 



Passing to the fleas, the most important and truly parasitic 

 form is the chigoe or gigger (Pidex penetrans), This abounds 

 in tropical America and the West Indies. The female insects 

 only attack man, and this they do for the purpose of securing 

 a lodgment for their offspring. They attack especially the 

 soles of the feet, between the toes and near the nails. In bad 

 cases the whole of the foot becomes affected. After the insect 

 has penetrated the skin its body swells enormously and becomes 

 a mere bag of eggs. This swelling causes active inflammation, 

 which terminates in suppuration and the formation of open 

 ulcers. The chigoe also attacks various animals. In addi- 

 tion to the common flea (P. irritans) other species infesting 

 animals are said to attack man occasionally. As regards those 

 degraded types of insects known as lice I can only afford space 

 to remark that five species have been recognised as human. 

 These are the head-louse (Pcdiculus capitis) ; the louse of the 

 eyelids (P. palpebrarutn) ; the clothes-louse (P. vestimenti) ; 

 the distemper louse (P. tabescentium) ; and the pubic louse (P. 

 inguinalis). The distress these creatures occasion is only fully 

 known to physicians who deal with the obstinate cutaneous 

 affections caused by their presence (PhtJiiriasis) . Some of the 

 lice found on negroes and Greenlanders are regarded as distinct 

 varieties. Lice are abundant on animals, and some of the 

 species are apt to transfer themselves from one host to another. 

 Thus the Ornithomyia avicularis of cage birds has been found 

 on man, whilst one or more of the numerous species infesting 

 the common fowl are, by transfer, apt to produce a severe 

 phthiriasis in the horse. The lice of the fowl belong to the 

 genera Leipurus, Isiotheum, Menopon, PJiilopterus, Goniodes, and 

 Goniocotes. The unsuitableness of man's person as a habitation 

 fur bird-lice should, however, check the fear which many persons 



