36 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 lirst 

 division of the thorax. 



C is a male Ijeptopsylla mtou'itU 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" by having 

 four genal spines instead of three. 



D is a male Ceratophyllus fascialus 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 Ceratophyllus x/ltintictri Wagn., the flea found on 

 the Mongolian marmot, Maniiota bobac Pallas, and responsible for 

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

 able from the common rat-flea (D). 



F is a female cat-flea, Ctrnoccjiluilux /<//* 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, Ctenocephalus can is Curtis, found on 

 cats as well as dogs. The flea resembles Ctenocephalus frlix, but 

 has the head more rounded. 



H is a male human flea, I'nlc.r irrihnix 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, "Dermatophilus jH-ni'lranx 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, Bra/il 

 and Argentina, the jij^or flea is now spread also over most parts 

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

 mammals brsidi-s man. 



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

 bugs and will bo referred to under their respective headings. 



