THE MICROPTERYGIDES. 138 



primitive genus of Lepidoptera, the lacinia being a rudimental, 

 scarcely functional, haustellum or tongue, and not merely a vestigial 

 structure, is of great significance from a phylogenetic point of view, 

 besides affording a basis for a division of the Lepidoptera into two 

 grand divisions or suborders, for which we would propose the name 

 LEPIDOPTERA - LACINIATA and LEPIDOPTERA - HAUSTELLATA " (Bombycine 

 Moths of America, p. 58). 



The imaginal mouthparts are perhaps the most unusual struc- 

 tures presented by these remarkable insects, and show most strikingly 

 Mecopterid and Neuropterid affinities. It will be well, therefore, 

 to examine these in detail. After stating that the mouth-parts of 

 the lower Micropterygina (i.e., the Micropterygids) exhibit several 

 most primitive characteristics, Walter shows that the maxilhe are 

 Constructed on the type of those of biting or mandibulate insects, i.e., 

 with an inner lobe (galea) and an outer lobe (lacinia) besides the palpi. 

 He writes of the first pair of maxilla? as follows : "In the first pair of 

 maxillae of Mtcropteryx calthella, aruncella, andersckella, and aureatdla, 

 cardo and stipes are present as two clearly separate pieces. The 

 former in M. calthella and M . aruncella, in comparison with the latter, 

 is larger than in M. anderschella and M. aureatella. In the last two 

 species, the cardo is still tolerably broad, but reduced. The stipes 

 is considerably longer than the cardo in the last two species, 

 whilst it is of the same thickness. From the stipes arises the large 

 G-jointed palpus maxillaris, folded two or three times, and con- 

 cealing the entire front of the head, and all the mouth-parts. At its 

 base, and this is unique among all the Lepidoptera, two entirely separate 

 maxillary lobes arise from the stipes. The external represents the most 

 primitive rudiment (anlage) of a lepidopterous tongue." 



With regard to this first pair of maxillae, Packard writes : " It is 

 evident from Walter's figures and description, that this structure is not 

 a case of reduction by disuse, but that it represents the primitive con- 

 dition of this lobe, the galea of the maxilla, and this is confirmed by the 

 presence of the lacinia, a lobe of the maxilla not known to exist in any 

 other adult lepidopterous insect, it being the two galeae, which become 

 elongated, united, and highly specialised, to form the so-called tongue, 

 haustellum, or glossa of all Lepidoptera above the Micropteryyidae (Erio- 

 cepkalidae) , which we may therefore regard as the types of the LEPIDOPTERA - 

 LACINIATA. Another most important feature correlated with this, and 

 not known to exist in LEPIDOPTERA-HAUSTELLATA, is the presence of two 

 lobes of the second maxillae, besides the three-jointed labial palpi, and 

 which correspond to the ' mala exterior ' and the ' mala interior ' of 

 the second maxillae of Dermaptera, Orthoptera, Platyptera, Perlidae, 

 Termitidae, and Odonata, and also, as Walter states, to the ligula and 

 paraglossre of Hymenoptera. In this respect the laciniate Lepidoptera 

 are more generalised insects than the Trichoptera or Mecoptera " 

 (American Naturalist, 1895, p. 637). 



Walter describes the second pair of maxilla?, each of which con- 

 sists of two lobes, the outer and inner mala as follows : " Within and 

 -at the base of the labial palpi is a pair of chitinous leaves provided 

 with stiff bristles, being the external second lobes of the underlip, 

 formed by the consolidation of the second pair of maxilla), and which 



* Jenaisch. Zeitsch.f. Naturwiss., v., 18 (1884) ; Ibid, v. (1885), pp. 751-807. 



