I. 



APTERA. 



INSECTS of this order are without wings, and the name is 

 derived from two Greek words, a, privative, and Trrcpdv, wing, 

 indicating the negative character which constitutes this order.* 

 It consists of Fleas and Lice. The Flea (Pulex), of which 

 De Geer formed a separate group, and called Suctoria, includes 

 several species. 



The common flea (Pulex irritans, Fig. 17) has a body of oval 

 form, somewhat flattened, covered with a 

 rather hard horny skin of a brilliant chestnut 

 brown colour. It is the breaking of this hard 

 skin which produces the little crack which 

 is heard when, after a successful hunt, one has 

 the happiness to crush one of these parasites 

 between one's nails. 



Its head, small in proportion to the body, is compressed, and 

 carries two small antennae, of cylindrical form, composed of 

 four joints, which the animal shakes continually when in motion, 

 but which it lowers and rests in front of its head when in a 

 state of repose. The eyes are simple, large, and round. The 

 beak is composed of an exterior jointed sheath, having inside 

 it a tube, and carrying underneath two long sharp lancets, with 

 cutting and saw-like edges. It is with this instrument that the 



* It is probable that one day the order Aptera will be superseded. The 

 absence of wings is not really a character of great value. De Blainville, Mollard, 

 Pouchet, Van Beneden, and Gervais, have made several attempts in that direction. 

 The fleas have been placed among the Diptera, and the lice among Hemiptera in 

 the " Traite de Zoologie Medicale" of these two last authors. 



