224 



THE ENTOMOLOGIST. 



^ 



basal segment is homologous with the sub- 

 mentum of the mandibulata, and is formed 

 by the coalescence of two sclerites, corre- 

 sponding to the two cardines or submaxillae. 

 The second is homologous with the men- 

 tum, and is formed by the coalescence of 

 two pieces, corresponding with the two sti- 

 pites or maxillae. The third, or terminal, 

 is homologous with the ligula, and is 

 formed by the union of the subgalea, galea, 

 intermaxillffi, and prasmaxillae. The basal 

 of the ligula is formed by the coalescence 

 along the median line of the two sub- 

 galeas. The lateral terminal lobes are 

 homologous with the galea, corresponding 

 witli the lobi superiores of Kirby. The 

 median terminal lobes are homologous 

 with the two intermaxill^e, and the two 

 prfemaxillffi united along the median line. 

 As regards Heymons' objection, that the 

 labial palpi in waterbugs are not sufficiently 

 varied ; compared with the labial palpi of 

 the mandibulata, this is certainly so, but 

 on comparing them with the extremely uniform rbyuchotal rostrum, one 

 finds that they are really sufficiently variable. If the complex maxillae 

 of the mandibulata have become in the Rhynchota simple, uniform, 

 unvarying stylets, why could not the labial palpi assume by degeneration 

 the little-varied forms they present in the latter order ? As a matter of 

 fact, there is a certain amount of variation in the labial palpi of water- 

 bugs. In liyocons and other Naucoridfe, they are merely tiny rudi- 

 ments ; in Benacus and other Belostomatidie, they are well developed. 

 They present rudimentary articulation in Mononyx^ while in Gelasto- 

 coris ( = Galgulus) they are triarticulate. 



As the great majority of present-day authors, even Heymons, con- 

 sider the rostrum to be labial, Leon concludes that his homologies, as 

 set forth above, can be considered correct. 



The 4-segmentate labium, as represented by Halobates, is discussed 

 briefly ; Leon considers the homologies more difficult to determine 

 than in the other type, but concludes that the statements made above 

 are probably correct. 



The paper is marred by a number of misprints, particularly in the 

 scientific names of the bugs. The only one likely to mislead is on 

 page 8, five lines from top, where " trois " should be " quatre." 



Labium of Sphcerodema ( = 

 Diploniichus) rustica (after 

 Leon). Sg. = Subgalea. Mn. 

 = mentum. Sn. = submen- 

 tum. PI. = Labial palpi. 

 Ip. = Inter- and prjB-maxil- 

 lae. G. = Galea. 



G. W. KiRKALDY. 



