Key to Flea Species of Veterinary Importance in Australia

1	Ctenidia absent	2
	With pronatal ctenidium (+/- genal ctenidium)	4
2	Thorax not reduced - the 3 thoracic segments together are much wider than the first abdominal segment	3
	Thorax reduced - the 3 thoracic segments together are shorter in width that the first abdominal segment; Two setae on head behind antenna; On birds, especially poultry, but also dogs, cats, rabbits	Echidnophaga gallinacea
3	Pleural rod absent - pleural rod is a vertical ridge that divides the mesosternum (thoracic plate above the the coxa of the 2nd pair of legs); Only 1 strong seta on a head behind antennae; On pigs, people, dogs, cats	Pulex irritans
	Pleural rod present	Xenopsilla cheopis
4	With pronatal ctenidium only	8
	With both pronatal and genal ctenidia	5
5	Genal ctenidium horizontal and formed of 8 or 9 spines	Ctenocephalides 7
	Genal ctenidium vertical or oblique, and formed of 6 or fewer spines	6
6	Genal ctenidium vertical with 2-4 spines; On rodents	Leptopsylla spp
	Genal ctenidium oblique, and formed of 4-6 elements; On rabbits, cats	Spilopsyllus cuniculi
7	Head elongate anteriorly (♀ head twice as long as high, but ♂ head as long as high); First 2 spines of genal ctenidium similar in length; Dorsal margin of hind tibia with 6 notches bearing stout setae	Ctenocephalides felis
	Head rounded anteriorly (in both sexes, less than twice as long as high); First spine of genal ctenidium noticeably shorter than second; Dorsal margin of hind tibia with 8 notches bearing stout setae	Ctenocephalides canis
8	Pronotal ctenidium with more than 24 spines (on the 2 sides combined); Row of 4-6 bristles on the inner surface of the hind femur; On poultry	Ceratophyllus gallinae
	Pronotal ctenidium with fewer than 24 spines (on the 2 sides combined); Inner surface of the hind femur bears 3-4 bristles; On rodents	Nosopsyllus

Adapted from: Wall & Shearer (2001), Soulsby (1982 and Beveridge & Gasser (1997)