432 CALIFORNIA ACADEMY OF SCIENCES. 



lated terminal lobes and segmented palpi, and a labium 

 composed of the fused second maxillae with similar basal 

 and terminal sclerites and segmented palpi. But the 

 Mallophagous mouth-parts represent a modified, a special- 

 ized condition of this simple type, in which the reduction 

 of the maxillce with the complete loss of their palpi and 

 (in one suborder) the loss of the labial palpi, so con- 

 fuse, at first glance, the homologies of the various struc- 

 tures, as to make the proper understanding of the mouth- 

 parts a matter requiring some special attention. 



Nitzsch, the first student of the Mallophaga, misun- 

 derstood the structure of the mouth-parts, holding the 

 labial palpi to be maxillary palpi (see figs, i, 2 and 3, 

 plate lx), and his error was not corrected until Grosse*, 

 in his careful dissections of Tetraof>Ji/Juih)uts chileiisis 

 \_=Menopon titan], made the matter plain. 



t Rudow gives a most confused account of the mouth 

 parts, having evidently made very superficial observa- 

 tion, although he declares himself to have made a most 

 careful and exhaustive study of them. He concluded, 

 from observation of the hypopharynx, that the Mallo- 

 phaga should be classed with the sucking insects, and 

 particularly with the Hemiptera. \ Melnikoff thought 

 the peculiar chitin structure in the pharynx (referred 

 to later as the oesophageal sclerite) to be homologous 

 with the sucking structures of the Pediculidae, and 

 therefore held the Mallophaga to be true sucking in- 



* Grosse, Franz. Beitrage zur Kenntniss der Mallophagen. Zeitsch. f . 

 wiss. Zool., vol. xlii, 530, p. pi. xviii, 1885. 



t Rudow, Fred. Beobacktungen iiber Lebenweise u. Bau der Mallo- 

 phagen o. Pelzfresser. Zeitschr. f. ges. Naturwiss., vol. xxxv, 1870, pp. 

 288-298. 



t Melnikoff, N. Beitrage zur Embryonalentwickluug der Insekten. 

 Archiv. f. Naturgesch., 1869. p. 136. 



