132 



HARDWICKE'S SCIENCE-GOSSIP. 



CHAPTERS ON ANIMAL PARASITES. 



By W. A. Hyslop. 



No. II. 



CLOSELY allied to the Diptera, though even the 

 traces of wings seem completely lost, are the 

 Aphaniptera, or fleas, a large and important division 

 of parasites, and, so far as I know, except for various 

 articles in magazines, undescribed. A number of 

 species are described and figured in Science-Gossip 

 for 1 87 1, p. 100. I do not intend entering upon any 

 description of the Aphaniptera, but would merely 

 point out that there is much scope for research in this 

 branch of entomology, as the various writers who 



Fig. 84.— Flea of Dog [Pulex cam's), male enlarged. 



Fig. 85. — Flea of Mole [Pulex talpa), male, enlarged. 



mention fleas show great variety of opinion as regards 

 the number of different species, some describing 

 about twenty varieties, while others, such as M. 

 Megnin, only mention about ten. M. Megnin seems 

 to consider that the species of other authors are all 

 identical with one or other of those described by him. 

 The size and number of combs on the head and 

 thorax seem one distinguishing feature. Among the 

 fleas should be mentioned the chigoe of South 



America, the female of which burrows below the toe- 

 nails, and causes much annoyance and pain. 



Passing over the Heteroptera, or bugs, which do 

 not fall under the definition of parasite adopted in 

 this article, we come to the Anoplura, or lice, and it 

 is to this division I wish more particularly to draw 

 attention. Before doing so, however, we may briefly 

 consider the remaining kinds of animal parasites, viz. 

 those of the genera Ixodes and Acari. 



The Ixodes, or ticks, are well known, and species- 



Fig. 86.— Flea of Bat [Pulex ■vespertilionis), male, enlarged - 



Fig. 87.— Chigoe [Pulex j>e>ietra?ts), enlarged. 



may be found on most of our quadrupeds, notably 

 the dog. They should, if one adhered closely to the 

 definition of parasite already given, be excluded, as 

 they live in the grass and underwood, and fix them- 

 selves to passing animals in order to suck their blood 

 and drop off when satisfied. The body of the female 

 expands when full of blood, being to a certain degree 

 elastic, while that of the male does not. The adult 

 specimens are always furnished with eight legs, but 



