80CTORIA. 359 



visible maxillary palpi, quadriar-ticulated antennae thicker near the 

 extremity, and an anterior mouth, that of LIOTHEUM. Here the man- 

 dibles are bidentate, the labial palpi distinct, and all the tarsi termi- 

 nated by two hooks. The species are found on various Birds, whereas 

 tin- Gyropi live on the Guinea-pig. A fourth and last genus, the 

 species of which are exclusively confined to Birds, is that of PHILO- 

 PTBRUS. The antennae consist of five joints, the third of which, in 

 the male, frequently presents a branch that forms a forceps with the 

 first; these organs are filiform. The maxillary palpi are invisible. 

 The tarsi have two hooks at their extremity, but they do not diverge 

 like those of the Liothea. Besides this, the males here have six 



s, three on each side, and their four biliary vessels are thickened 

 near the middle of their length. Those of the Trichodectes and 

 Philopteri do not exhibit this enlargement, and they have but four 



is, t\vo on each side. In these two genera there are also ten 

 ovaries, five on each side; in such of the female Liothea as this 

 sevant could find them, he saw but six, three on each side. He has no 

 positive knowledge of the number of these in the female Gyropi, 

 nor of that of the testes in the males. In all these genera the thorax 

 is bipartite, that is, the prothorax and the mesothorax compose the 

 apparent trunk, and the third division, or the metathorax, is united 

 to the abdomen and confounded with it. M. Kirby was the first, I 

 think, who thus designated this segment ; but Nitzsch, on the other 

 hand, seems to have first employed the others*. The limits of this work 

 interdict any exposition of the subgenera he has established. We will 

 merely remark that the one he calls Goniodes, the fourth subgenus 

 of Philopterus, is exclusively proper to the Gallinaceae. In the col- 

 lection of memoirs which terminates our Histoire des Fourmis, we 

 have minutely described a species of Ricinus Philopterus, Nitzsch. 



M. Leon Dufour, with the P. melitece of Kirby, previously well 

 observed by De Geer, who considered it as the larva of the Metoe 

 proscarabceuSt as well as by that celebrated entomologist, has formed 

 a new genus Triongidin des andrenettes the characters of which 

 he has figured and published in the Ann. des Sc. Nat. XIII, 9, B. 

 11 this Insect be not the larva of that Meloe, as in the opinion of M. 

 Kirby, there is no doubt but that it forms a peculiar subgenus in the 

 order of the Parasita; but according to the researches of MM. Le- 

 peleticr and Servile, the idea of De Geer is confirmed. 



ORDER IV. 



SUCTORIAf. 



The Suctoria, which constitute the last order of the Aptera, have a 

 mouth composed of three \ pieces, enclosed between two articulated 



* See our general observations on the class of Insects. 



f Siphonaptera, Lat. 



J Roescl represents but two; Kirby and Straus, however, have observed one 

 more. According to the latter, the two scales which cover the base of the rostrum 

 are palpi. 



