Dr. Karl Kiapelin on the Pulicidss. 43 



this, however, we must not forget that maggot-like larvae also 

 occur in groups far removed from the Flj-type, in Hymeno- 

 ptera and Beetles, and therefore cannot possibly be of decisive 

 importance in judging of relations of affinity ; as also, on 

 tlie other hand, that the pupa of the Fleas witli its quite 

 separate Hmbs differs so much at least from the general 

 type of the mummy-pupre, that from this very fact it has 

 been attempted to set up a relationship of the Fleas to the 

 Hymenoptera *. Hence the point of the question how far 

 the analogous characters in Diptera and Pulicidgs depend 

 upon true phylogenetic affinity would have to be sought 

 in the investigation whether the construction of the sucking- 

 apparatus is carried out in both cases on the same plan, 

 i. e. with the same employment of homologous parts. That 

 it is only from this discussion and from that as to the 

 structure of the thorax and its appendages that a real decision 

 of the question before us can be arrived at, may indeed be 

 deduced from the consideration that in these organs we find 

 the only characters which, on the one hand, are confined to 

 the order Diptera, and, on the other, may be traced tlirougli- 

 out their whole series of forms, and therefore must be regarded 

 jcar' e^ox')*' ^S typical. 



The structure of the buccal apparatus of the Pulicidas has 

 been very frequently discussed without the question of its 

 relationship to the sucking-apparatus of other groups of 

 insects having as yet been solved. Thus to cite only a 

 few : — Dug^s f thinks that the proboscis of the fiea may be 

 placed side by side with that of the Tabanidas, but also finds 

 resemblances to the Hippoboscidae and Apidre. L. Landois| 

 suggests a resemblance of the mouth-apparatus of the Puli- 

 cidai to the rostrum of the Hemiptera ; while Taschenberg§, 

 again, thinks he recognizes the Dipterous type, and espe- 

 cially calls attention to the presence of a " tongue " as 

 the most characteristic part of the moutli of a fiy. This ex- 

 traordinary diversity of opinions is principally to be ascribed 

 to the uncertainty of the interpretation of this very " tongue " 

 of Taschenberg's. The mandibles, maxillas, and labium 

 have long since been recognized with certainty ; but the un- 

 paired piercer " (to express myself neutrally) has been referred 

 to as the labrum (Westwood, HaJler, Bonnet), as the hypo- 



* As by Duges, hi his " Reclierches sur les characteres zoolog-iques 

 du genre Pulex," in Ann. Sci. Nat. tome xxvii. p. 157. 



t Loc. cit, p. 151. 



i L. Landois, ''Anatomie des Ilimdeflolies," in JSTova Acta Acad. 

 Leop.-Car. 1866, p. 56. 



§ Loc, cit, p. ■11. 



