CYLINDROTOMINA. 295 



the absence of the small cross-veiu on the wings, and the sculp- 

 ture of the thorax remind of Triogvia so much, that before I 

 had seen G. glahrata,, I preferred to place G. nodicornis in the 

 genus Triogma, rather than to connect it with G. americana 

 (compare my description of this species in Proc. Entoin. Soc. 

 Philad. 1865). The fact is that these species represent a grada- 

 tion which baffles every attempt at a generic arrangement. 



The North American Phalacrocera tipuUaa 0. S. shows an 

 important difference in the venation from the typical Phalacro- 

 cera, the European P. replicata ; but the resemblance in their 

 coloring and general appearance is very great. 



In order to avoid the establishment of a new genus for almost 

 every species known, which would probably necessitate a similar 

 process for every species to be discovered hereafter, I have pre- 

 ferred to retain Dr. Schiuer's three genera, although since the 

 discovery of the North American species those genera rest more 

 upon the general appearance of the insects than upon characters 

 which admit of a strict definition. Acting upon this principle, 

 I have placed in the genus Gylindrotoma, the insect which I had 

 described in 1865 under the name of Triogma nodicornis. 



4. Larv^. 

 The early stages of the Ci/lindrotomina seem to be as anoma- 

 lous as the structure of the perfect insect. The larva of G. dis- 

 tinctissima, instead of being found underground, or in decayed 

 wood or in fungi, like most tipulideous larvae, assumes the habits 

 and more or less the exterior of a lepidopterous larva, and lives 

 ^pon the leaves of certain plants. The larva of Phalacrocera 

 replicata, still more singular in structure, lives under water, upon 

 water plants (more details about both larvae will be given below). 



5. Geographical Disteibution. 

 Besides the six species from the old world and the four from 

 North America, which have been mentioned on the preceding 

 pages, no other described Gylindrotomina can be named here 

 with any degree of certainty. Gylindrotoma albitarsis, from 

 Java, described by Doleschall, Natuurk. Tijdschr. Nederl. Indie, 

 Yol. XIY, p. 15, Tab. lY, fig. 1, can hardly be a Gylindrotoma, 

 and its venation seems to show some analogy to that of Limnohia 

 trentepohlii Wied. {Auss. Zw. I, p. 551, Tab. YI, h, fig. 12), from 



