which later investigators could advance, and we consequently find them confining 

 their attention to minor anatomical points, or to discussions of how many and 

 which of the mouth-parts are really homologs of legs, and to homologizing the 

 coxal, femoral, tibial, or tarsal parts of insects' legs with portions of their 

 mouth-parts. Savigny had already expressed his opinion (p. 41 of his second 

 memoir), that, besides the paired organs, the under lip " can be considered as 

 formed by the union of the two second maxillae." * 



ERICHSON, 6 in 1840 (p. 4-7 of . his Entomographieri), discusses the mouth- 

 parts of insects, devoting the greater part of his space to the consideration of 

 the under lip, which he regarded as originating in the union of a pair of organs, 

 in fact, speaking of it throughout his paper as the third pair of jaws. ** He 

 says (p. 4-5) "The third mandibular pair forms, in insects proper, a constant 

 part of the under lip, which is formed by the union of this pair with the mentum 

 and with the tongue (ligula). This third pair has the mentum behind and 

 beneath, and the ligula above and before it, but is always characterized by 

 labial palpi which belong to it." *** He further adds (p. 7), " In the two 

 other orders of insects with sucking mouth-parts, the diptera and hcmiptera, the 

 coalescence of the third pair extends still further upon the palpi, which form the 

 tubes of the proboscis, and surround the remaining bristle-formed mouth-parts." f 

 In the male of Culcs I have found, as will be more fully described later, a 

 somewhat analogous case of union of the tongue with the labium ; that is, ana- 

 logous, if one assumes the tongue, of Erichson, to be the hypopharyux, of Sa- 

 vigny, an assumption which may be incorrect, since Erichson fails to define clearly 

 what he means by tongue, or ligula. It is furthermore very probable that, as 

 Savigny stated, the labial palpi are absent in diptera, and I find nothing, in my 

 own observations, or in those of others so far as I have compared them, to show 

 that the proboscis of diptera is, in any way, the product of labial palpi. The 

 homologies found in Ericbson's paper are of doubtful value, at least so far as 



* "(^u'on peut considerer comme fornx'e par la reunion ties deux secondes machoires.'' 

 ** "Das dritte Kieferpaar." 



* li Das dritte Kieferpaar maclit bei den eigentlichen Insecten bestandig einen Theil 

 der Unterlippe aus, welclie durch die Vereinigung desselben mit dem Kinn (mentum} und 

 der Zunge (ligula) gebildet wird. Dieses dritte Kieferpaar hat nun das Kinn hinter und 

 unter, und die Zunge ubcr und vor sich, wird indess immer durch die ihra angehorenden 

 Lippentaster bemerkbar." 



j- "jBei den beiden andern Ordnungen der Insecten mit saugenden Mundtheilen, den 

 Dipteren und den Hemipteren, erstreckt sich das Yerwachsen des dritten Kieferpaares noch 

 welter auf die Taster, welclie die Rohre des Riissels bilden, und die iibrigen borstenformigen 

 Mundtheile umschliessen." 



