66 Journal New York Entomological Society, t"^'"' >^xix, 



nectiou I need but cite the universally accepted, though erroneous, 

 conclusion that the " superlinguse " of insects (which are the honio- 

 logues of the paragnaths of Crustacea) represent the first maxillse 

 (maxillulse) of Crustacea, and the resultant false conclusions that 

 the first maxilke of insects (which are homologous with the first 

 maxillae or maxillulse of Crustacea) represent the second maxillae of 

 Crustacea, while the second maxillae (labial appendages) of insects 

 are incorrectly homologized with the first maxillipeds of Crustacea, 

 instead of correctly homologizing them with the second maxillae of 

 Crustacea. As a consequence of these false views, the head of an 

 insect is regarded by some entomologists as composed of seven seg- 

 ments (instead of but six, as embryology has long shown to be the 

 case), and the true homologies of the structures of the head of an 

 insect have been greatly confused. 



Not only has the composition of the head in general been misin- 

 terpreted by many entomologists, but the nature of the parts of the 

 mouth structures has not been properly understood, due to the fact 

 that no one has apparently made a thoroughgoing comparison of 

 these structures in insects, Crustacea and trilobites. Thus Chatin, 

 Smith, and other entomologists who are apparently not aware of the 

 fact that the mandible of an insect represents only one segment of a 

 modified limb, while the '"body" of the maxilla (not including the 

 cardo and palpus) is composed of at least tzvo segments of such a limb, 

 have made the unfounded claim that the parts of the maxilla are re- 

 peated in the mandible ; and such investigators as Hollis, 1872, or Hey- 

 mons, 1896, who have mistaken the lacinia mobilis and processes of 

 the incisor region of the mandibles of insects for so called mandi- 

 bular " palpi," homologous with the mandibular palpi of Crustacea, 

 are apparently not familiar either with the nature of the mandibular 

 palpi of Crustacea, or with the structure of mandibles in various 

 insects, since the structures occurring on the mandibles of insect's 

 which they attempt to homologize with the mandibular palpi of 

 Crustacea, do not occur in the same position occupied by the palpi 

 of the latter forms, and they have nothing of the nature of palpi to 

 warrant interpreting them as such. 



The fact that entomologists homologize the palpi of the maxillae 

 (or labium) with the exopodite of a crustacean limb, and homologize 

 the galea and lacinia of the maxillae with the endopodite of such a 



