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6 Guide to Insects and Ticks 



having three spines on the lower edge (gena) of the head. There 

 is also a comb of spines projecting back from the pronotum or first 

 division of the thorax. 



C is a male Lcptopsijlla iiinsculi Duges, the common flea of the 

 mouse, but also found on the rat. Though primarily European, 

 it is now almost cosmopolitan. It has a comb of spines on the 

 pronotum, but no eyes, and is distinguishable from "B"' In" having 

 four genal spines instead of three. 



D is a male Ceratophi/Uus fasciatus Bosc, a common rat-flea, 

 almost cosmopolitan in distribution. It has eyes, and a comb of 

 spines on the pronotum, but no genal spines. 



E is a male Geratophyllus silantieici Wagn., the flea found on 

 the Mongolian marmot, Marmota bohac Pallas, and responsible for 

 the spread of pneumonic plague. It is with difhculty distinguish- 

 able from the common rat-flea (D). 



F is a female cat-flea, Ctcnoccphalus felis Bouche, found not 

 only on cats, but also on wild species of felidae, and on dogs. It 

 is widely distributed, and is distinguished by having eyes, a comb 

 of spines on the pronotum, and a row of eight spines (genal spines) 

 at the lower edge of the head. 



G is a female dog-flea, Ctcnoceplialus canis Curtis, found on 

 cats as well as dogs. The flea resembles Ctcnoccphalus fells, but 

 has the head more rounded. 



H is a male human flea, Pitlex irritcuis Linn. This flea is 

 short and thick-set, with eyes, but no comb of spines on the 

 pronotum. It is almost cosmopolitan in distribution. 



J is a young female jigger flea, Dcrmatopliilus pcnctratis Linn. 

 The female jigger flea burrows into the human skin, and its 

 abdomen becomes so enormously distended with eggs as to attain 

 the size of a small pea. The part of the skin affected may become 

 ulcerated and infected with various pathogenic bacteria, and so 

 lead to serious consequences. Although a native of Mexico, Brazil 

 and Argentina, the jigger flea is now spread also over most parts 

 of tropical Africa, and has even reached India. It attacks other 

 mammals besides man. 



The slides K, L and M are preparations of a louse and two 

 bugs, and will be referred to under their respective headings. 



