298 ROBERT E. SNODGKASS. 



to the maxillae, and he described the labium as having small 1- or 

 2-jointed palpi. He did not, however, mention the oesophageal 

 sclerite and lingual glands of the Ischnocera, nor did he perceive 

 the maxillary forks which are present at least in some forms. 



In 1870 Rudow (2) published detailed accounts of the mouth- 

 parts of a large number of Mallophagan species. He makes, how- 

 ever, the curious and unaccountable error of ascribing to Ischno- 

 ceran forms a 5-8-segmented maxillary palpus and a 3 segmented 

 labial palpus, and to Amblyceran forms a 5-segmented maxillary 

 palpus and a 4-segmeuted labial palpus. One would suppose he 

 had taken the antennae for palpi, but the antennae he describes also. 



Giebel (3) in 1874, following Nitzsch's work, gives correct de- 

 scriptions and figures of the mandibles, maxillae and labium, show- 

 ing the 4-joiuted palpi of the Amblycera as appendages of the 

 maxillae. 



In 1878 Burgess (4) gave the first good account of the Corroden- 

 tian mouth-parts. He described the large biting mandibles, the 

 maxillae bearing each a 4-segmented palpus and one weakly devel- 

 oped apical lobe, and the simple labium with small 1-segmented 

 palpi. Furthermore, he described and figured the curious oesopha- 

 geal sclerite (or " oesophageal bone"), the lingual glands and the 

 maxillary forks. The latter he called simply the "forks" and re- 

 garded them as morphologically independent of the maxillae He 

 described the muscles connecting them with the stipes and apical 

 lobe of the maxilla, and an "elastic ligament" extending from the 

 inner end of each to the wall of the head. 



In 1885 Grosse (5) published a new opinion concerning the palpi 

 of Mallophagan suborder Amblycera. He states that in dissections 

 of the mouth parts the palpi always come away from the head with 

 the labium. He consequently regarded them as labial palpi, and 

 gives figures of the labium of two species, each bearing a pair of 4- 

 jointed palpi. He of course, therefore, described the maxillae as 

 being always small and weakly developed and as never possessing 

 palpi. 



In 1887 Packard (6) made the first intelligent comparison be- 

 tween the Mallophaga and the Corrodentia. He based his compari- 

 sons on the anatomical work of Burgess and Grosse. But, since 

 Grosse described the labium of the Mallophaga as bearing palpi and 

 the maxillae as lacking them, and since the oesophageal sclerite, lin- 



