190 A nuaJs Entomological Society of America [Vol. X, 



must also be considered as representing entire segments, if their 

 homologue, intersegmental region I, is taken to represent a 

 distinct segment. Verhoeff, 1902-1903, clearly realized that 

 it was impossible to consider intersegmental region I (i. e. the 

 neck) as a distinct segment, without likewise regarding its hom- 

 ologues,' intersegmental regions III and V, as representing entire 

 segments also, since all three regions are in every way exactly 

 homologous. Verhoeff, 1904, therefore boldly accepted the 

 consequences of his assumption, and claimed that the thorax 

 actually consists of six segments, terming the intersegmental 

 regions the " microthorax, stenothorax and cryptothorax, " and 

 making them the equivalents of the prothorax, mesothorax and 

 metathorax. Embryology, however, affords no evidence of 

 more than three segments in the thorax, nor does the evidence 

 of comparative anatomy give any grounds for considering that 

 these intersegmental regions represent distinct segments, since 

 none of them contains any ganglia or other segmental struc- 

 tures — as was pointed out by Silvestri, 1902, Boerner, 1903, 

 Desguin, 1908, and others — and no recent entomologist has 

 had the courage to claim that the thorax is composed of more 

 than three segments. 



Some entomologists, however, ignoring the fact that inter- 

 segmental region I (Figs. 1, etc.) is in every way homologous 

 with intersegmental regions III and V, would maintain that 

 intersegmental region I (i. e. the neck region) alone represents 

 a distinct segment, claiming that it is the real labial segment. 

 Since the labium ("L" of Fig. 1) does not articulate with the 

 plates of intersegmental region I, but articulates with the 

 sclerite designated as " 7y' ' (which contains the real labial 

 segment) in the head capsule, these entomologists are forced 

 to the astonishing conclusion that the labium has become 

 detached from its own segment, and, taking along with it the 

 labial neuromere (or labial ganglion) and other characteristic 

 segmental structures, has migrated "bag and baggage" into 

 the head region, leaving behind it the mere shell of the labial 

 segment in the neck region I ! Such a disruption and migration 

 of both internal segmental structures and external appendages, 

 which have in some way become detached from their proper 

 segment, and have grafted themselves onto another region, is 

 wholly without precedent in the entire realm of Zoology, for 

 never did such an occurrence take place other than in a labora- 



