CHAPTER XXXIV 



SIPHONAPTERA AND COLEOPTERA 



Siphonaptera — Sarcopsyllidae- — -Dermatophilus penetrans — Pulicidae — Pulicinae 

 — ■ Pulex irriians — Xenopsylla cheopis — Coleoptera — Orthoptera — 

 References. 



SIPHONAPTERA Latreille, 1825. 



Synonyms. — Rophoteira Schellenberg, 1798; Aptera Lamarck, 1801; 

 Aphaniptera Kirby and Spence, 1S26; Pulic idee Stephens, 1829. 



Definition.— Hexapoda with laterally compressed bodies and dis- 

 tinctly separated thoracic rings. Wings absent, except for two 

 lateral plate-like appendages on the meso- and meta-thorax. 



The antennae are three-jointed, and embedded in grooves. The 

 third joint has nine more or less separated pseudo-joints. 



Remarks. — Fleas have come into considerable prominence, 

 owing to the work of the Indian Plague Commission and that of 

 Dr. Verjbitski, of St. Petersburg, who have shown that they are to 

 be looked upon as the main agents by which plague is spread from 

 rat to rat, and from rat to man. 



Fleas may also carry blood-parasites — as, for example, Trypano- 

 soma lewisi — and, again, they may serve as intermediary hosts for 

 the cysticercus of tapeworms, as in the case of Dipylidinm caninum. 



History. — ^The knowledge concerning fleas is of recent date. In 

 1758 Linnaeus started with one genus and species, Pulex irritans ; 

 the second genus was that of the Chigoe in 18 15, under the term 

 Rhynchoprion penetrans ; and the third genus was created by Curtis 

 in 1832 under the heading Ceratophyllus. The first general syste- 

 matic treatise was by Kolenati in 1863, the second by Taschen- 

 berg in 1880, and the third by Baker in 1904. 



Recently much work has been done on these parasites by 

 Rothschild and Jordan. 



Morphology. — The head is small, and may or may not possess eyes, which, 

 when present, are only simple pigment masses. Directly behind the head is 

 the antennal groove, in which the antennae, which are important organs to 

 the flea, lie protected from harm. This groove is continued upwards to the 

 mid-line of the vertex by an incrassation which divides the frons from the 

 occiput. The groove may be open or closed by a process of the gena. 



The antennae are composed of three joints, of which the third, often called 

 the club, may be unsegmented, segmented on the posterior border only, or 

 completely segmented into nine more or less separate pseudo-segments. 



The frons may carry a tubercle or notch, situate rather nearer the mouth 

 than the centre of the head, while laterally the eyes, when present, are to be 

 seen. The area of the head below the eyes and extending from the perioral 



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