86 

 SUCTORIA. 



J. B. Tyrrell, B.A., F.G.S., of the Geological and Natural 

 History Survey op Canada. 



& 



Read nth February, IS84.. 



It would be almost a truism to say that we ai'e indebted to Lin- 

 naeus for first giving the fleas a systematic ])osition in the animal 

 kingdom. He ranked them under the genus pulex, and placed this 

 genus, along with many other dissimilar ones it is true, in the order 

 aptera, an order under the class insecta. Lamarck also placed them 

 under the same order, and it was left for Latreille in 1805 A.D. to 

 separate them under the name suctoria, though he afterwards aban- 

 doned it and adopted the name siphonaptera for these insects. In 1826 

 Kirby and Spence used the name aphaniptera for the same group, 

 which is that ordinarily used in English books on entomology. In 

 1844 Gervais described all the species then known of the genus pulex, 

 in a work by Walkeraer and Gervais on "Aptera," a work which is 

 still the principal book of reference on all the so-called ajiterous insects. 

 In 1867 Landois gave us a careful description of the anacomy of the 

 dog-flea [Pulex cams), and in 1880 O. Taschenberg in an exhaustive 

 paper redescribed all the species that were tlien known,' and after a 

 careful examination of those found on a number of difierent animals 

 considered that, with the excei)tion of cen described species which he 

 had not seen, all could be referred to 24 species grouped under five 

 genera. 



The insect itself, as most of you are aware, is of a dark brown 

 colour and from ^^ to i in. in length, according to the species to which 

 it belongs ; is strongly compressed laterally, and possessed ot powerful 

 legs adapted for leaping. The head is relatively small, usually rounded 

 on the upper side, aiid in most species more or less evenly curved from the 

 neck to the point of insertion of the oral appendages. The hinder border 

 of the head projects in two wing-like chitinous processes, which are 

 inserted between the wings of the thorax, while at the same time the 

 hinder border of the head overlaps the front of the thorax in its whole 

 extent. This is noticeable, as it is very diflerent from the arrangement 



