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An Introduction to Medical Entomology

For educational purposes. Quote cited references only.

 

Insecta

KEY TO SIPHONAPTERA

OF MEDICAL IMPORTANCE

(Fleas)

(Contact)

 

Please CLICK on picture and underlined links to view or to navigate within the key:

To Search for Subject Matter use Ctrl/F

[Also See: Siphonaptera Details]

 

There are about 221 genera and over 2,205 species of fleas in the world. The order has five families with species of medical importance: Hectopsyllidae, Dolichopsyllidae, Pulicidae, Hystrichopsyllidae and Ischnopsyllidae. Thirteen medically important species are: Ctenocephalides canis (Curtis) [dog flea], Ctenocephalides felis (Bouche) [cat flea], Cediopsylla simplex (Baker) [rabbit flea], Ceratophyllus gallinae (Schrank) [chicken or hen flea], Ctenophthalmus pseudargyrtes Baker [Small mammal flea], Echidnophaga gallinacea (Westwood) [stick tight flea], Hoplopsyllus anomalus Baker [rodent flea], Leptopsylla segnis [European mouse flea], Nosopsyllus fasciatus (Bosc.) [rat flea], Oropsylla montana (Baker) [ground squirrel flea], Pulex irritans L. [flea of humans], Tunga penetrans L. [jigger flea] and Xenopsylla cheopis (Roth.) [Oriental rat flea]. The common names of fleas (e.g. "dog flea") are misleading as humans may also be attacked by any of these species especially when in close proximity of the preferred host. New discoveries of medically important species are being made in South America; e.g., Ectinorus insignis (Beaucournu et al 2013) and Ctenidiosomus sp. (Lopez-Berrizbeitia et al. 2015).

 

The following keys separate the most common Genera and Species involved: [Please CLICK on Figures to view]

 

 

 

KEY TO PRINCIPAL IMPORTANT GENERA

 

 

1a. Combs and Meral Rods on thorax are present (Fig. A, Fig. B, Fig. C) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2a

 

No combs are present on thorax (Fig. D, Fig. E, Fig. F) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 4a

 

2a. Meral rod on lateral thorax is vertical (Fig. C) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Nosopsyllus spp. (species)

 

Meral rod is angled (Fig. A, Fig. B) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 3a

 

3a. Meral rod on lateral thorax is strongly angled (Fig. B)- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Leptopsylla spp. (species)

 

Meral rod is not as strongly angled (Fig. A) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Ctenocephalides spp. (species)

 

4a. Meral rod is present on lateral thorax (Fig. F) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Xenopsylla spp. (species)

 

No meral rod is present on lateral thorax (Fig. D, Fig. E) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 5a

 

5a. Antenna on head extends beyond an eye and first three thoracic segments about equal in size (Fig. D) - - - - - - - - - - - Pulex spp. (species)

Antenna is shorter, not extending beyond eye and first three thoracic segments are unequal in size (Fig. E) - - - - - - - Tunga spp. (species)

 

 

KEY TO PRINCIPAL IMPORTANT SPECIES

 

 

1. A greatly reduced thorax, with terga combined being shorter than the 1st abdominal tergum. Gravid females are greatly distended (Fig. 1) _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Hectopsyllidae

 

The thorax is not reduced and the combined terga are usually longer than the first abdominal tergum (Fig. 2) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 3

 

2. Third leg coxa with a patch of small spines on the inner surface. Abdominal segments 2 & 3 have spiracles (Fig. 3) _ _ _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Echidnophaga gallinacea

 

Coxa of 3rd leg lacks the small spines. Segments 2 & 3 of female abdomen lack spiracles. Species confined to warmer climates _ _ _ _ _ _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Tunga penetrans

 

3. Terga of abdomen usually with only one cross row of setae (Fig. 4). A groove between the frons and occiput is usually absent. Eyes are

usually present _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Pulicidae 4

 

Abdominal terga usually with more than one cross row of setae; There is usually a groove between the frons and occiput. _ _ _ _ _ _ _ _ _ 9

 

4. A genal comb, or crenidium is absent (Fig. 5c) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _5

 

Genal and pronotal combs are present (Fig. 5a) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _7

 

5. Pronotal comb or ctenidium is absent (Fig. 5c) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _6

 

Pronotal comb is present. Flea usually found on ground squirrels (Fig. 5g) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Hoplopsyllus anomalus

 

6. Thorax second segment pleuron divided by a stout, vertical rod like thickening _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Xenopsylla cheopis

 

Pleuron is not divided _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Pulex irritans

 

7. Genal comb teeth are straight, blunt and with black spines arranged almost vertically (Fig. 5i). usually found on rabbits in North America _ _

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Cediopsylla simplex

 

Genal comb teeth hve 7-8 sharp teeth, and are arranged almost parallel to the flea's long axis (Fig. 5a) _ _ _ _ _ _ Ctenocephalides spp. 8

 

8. The frons is high and rounded. The first 2 spines of the genal comb are shorter than the remaining (Fig. 5b) _ _ _ _ Ctenocephaldes canis

 

Frons is low, flat and almost pointed. Spines of the genal comb are about of equal length (Fig. 5a) _ _ _ _ _ _ _ _ _ Ctenocephalides felis

 

9. The head is a bit elongated and 2-3 ventral flaps are present on each side near the fronto genal angle (Fig. 5i). These fleas of parasites of

bats. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Ischnopsyllidae

 

Head is not elongated and there are no ventral flaps. Fleas are not bat parasites _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 10

 

10. A genal comb is absent, but combs on abdominal terga are often present. Hexactenus ischnopsyllus _ _ _ _ _ _ _ _ Dolichopsyllidae 11

 

The genal comb is present, but the combs on the abdominal terga are often present _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Hystrichopsyllidae 12

 

11. The pronotal comb has 12 or more spines on each side _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _Ceratophyllus gallinae

 

Pronotal comp has less than 12 spines on each side (Fig. 5d). On male the finger of clasper is short, broad, flattened and has spines but no

black spinifrons _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _Nosopsyllus fasciatus

 

The movable finger of the clasper is elongated and sword-shaped. Attacks ground squirrels that carry plague (Fig. 5e) _Oropsylla montana

 

12. The genal comb contains 3 sharp teet that are directed backward. Usually found on small rodents _ _ _ _ _Ctenophthalmus pseudargyrtes

 

Genal comb has 4 blunt teeth directed backwards. (Fig. 5h). Common on rodents _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Leptopsylla segnis

 

 

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Key References: <medvet.ref.htm> <Hexapoda>

 

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