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CHAPTER III. 
APHANIPTERA, 
(NOW INCLUDED IN NEMATOCERA.) 
Tue Aphaniptera are also known under the following names : 
Suctoria, De Geer. 
Siphonaptera, Lat. 
Aptera, Lam. 
The following may be taken as the characters of the section or 
sub-order and thus of the family Puticipz&: 
Parasitic, with scale-like rudimentary wings, the metathoracic scales 
being the largest. Tarsus five-jointed ; antenne small; mouth 
formed for suction, composed of mandibles and lingua, long; 
maxillz small, in form of triangular scales with four-jointed palpi ; 
labium minute, three-jointed ; palpi four-jointed. 
There are four genera: 1. Pulex; 2. Sarcopsylla (the latter not 
being British) ; 3. Aystrichopsylla, and 4. Typhlopsylla. 
The history and changes of the “fleas” have been known since 
the days of Aristotle. He noticed their distinct sex, and that they 
produced oxwans wordeis. He did not trace the changes of this insect 
far enough, and thus fancied this progeny was suz generis. He also 
thought that the adults were generated in the earth spontaneously. 
This spontaneous generation has been held up by many naturalists 
since his time, and has been applied to many of the invertebrate 
animals. I have even, in this nineteenth century, heard people 
talking of the spontaneous generation of “green fly” and locusts ; 
but happily this absurd notion is only lingering on amongst very few 
people. Few animals have had so many theories applied to their 
origin as the common flea; Scaliger thought they were produced 
from humours amongst the hairs of dogs. By degrees their true 
history became known, and to De Geer we are indebted for one of 
the first good accounts of their transformations. They have attracted 
attention in all parts of the world. ‘They were formerly thought to 
