434 



NATURAL HISTORY OF ARTHROPODS. 



OKDER IX. - - APHANIPTERA. 



The fleas are united with the Diptera by many entomologists, but at the present 

 time the weight of authority is in favor of their separation as a distinct order under 



the above name. The characters which separate them are a 

 thorax in which the three segments are distinct and nearly 

 equal, the two last rings (mesothorax and metathorax) bear- 

 ing short leaf-like appendages ; and mouthparts adapted for 

 piercing. 



The order forms but a single family, the PULICID^E, em- 

 bracing, besides the well-known fleas, the jigger-flea of South 

 America. They are wingless insects with compressed bodies, 

 small, round eyes, and mouth-parts adapted for sucking. The 



FIG. 550. Pulex irritans, flea. 



legs are long and stout, the hind pair especially so, giving 

 these animals their well-known leaping powers. The relation- 

 ship of the order to the Hemiptera, Diptera, and Orthoptera are well marked. 



In the genus Pulex, which embraces the fleas proper, the under lip is well devel- 

 oped. There are many species known, all of which lead a semi-parasitic life upon 

 man and various other mammals. The eggs are laid on the hair of the host, from 

 which they fall to the floor or ground, when the larvae hatch and feed upon refuse of 

 various sorts. The larval stage lasts about two weeks, and is followed by a pupal con- 

 dition of about the same duration. 



Fleas are very common upon cats and dogs, from which they frequently pass to 

 the human being, causing considerable annoyance by their bites. The best preventa- 

 tive is Dalmatian insect powder (the pulverized flowers of Pyrethruni) which should 

 be thoroughly rubbed into the hair of the victim. The kennels of dogs, and the 

 mats upon which the cat sleeps, should also 

 be occasionally sprinkled with the same 

 powder. 



The other genus of the group, Sarcop- 

 sylla, contains the famous jigger, chigoe, 

 chique, or pique of tropical America. The 

 adult female attacks any exposed portion 

 of the body, especially the feet, and soon 

 effects a lodgment beneath the skin. Here 

 the abdomen of the parasite soon becomes distended with eggs, so that a painful or 

 even dangerous ulcer is formed. Unless the female is soon extracted, the ulcer becomes 

 filled with a large colony of jiggers. From the egg hatches out a larva very like that 

 of the other genus, which lives upon the ground, there undergoing its transforma- 

 tions. 



J. S. KlNGSLEY. 



FIG. 551. Sarcopsylla penetrans, female distended 

 with eggs. 



