Biology of the North American Crane' 

 FHes (TipuHdae, Diptera) 



II. LIOGMA NODICORNIS Osten Sacken 



CHARLES PAUL ALEXANDER 

 ITHACA, N. Y.* 



The geuus Liogiiia belongs to the tribe Cylindrutomini, an 

 interesting group of the Tipulidaj. Baron Osten Sacken in the 

 Monograplis of the North American Diptera speaks of thera 

 as a "small, but very remarkable group of species, occupying 

 an isolated and intermediate position between the Tipulidm 

 brevipalpi and longipaljn." The structure of the adult flies, 

 especially as regards certain details of the venation of the 

 wings, is quite unique but it is in the immature stages of the 

 different genera that the most interesting distinctions are 

 found. Tlie larva, instead of living in the mud along the banks 

 of streams or in rotten wood as do the majority of the known 

 crane-fly larv?p, dwell upon the leaves of various terrestrial 

 and aquatic jilants; instead of being brown or grey in color, 

 they are bright green and usually resemlile the leaves of their 

 host-plants to a very remarkable degree. 



The larva of Cylindrotoma distinctissima Meigen lives on 

 the lower surface of the leaves of various plants {Stellaria L., 

 Anemone (Tourn.) L., ViuUi (Tourn.) L.) and eats elongated 

 holes in them. The larva before iindergoing its transforma- 

 tions, leaves its host-plant and crawls to some grass-stalk, 

 where it passes the pupal stage. The larva of Triogma trisul- 

 cata Schummel, is aquatic, living on the leaves of the submerged 

 moss, Fontiiialis antipyretica L., in small alpine streams where 

 it was first found in Saeckingen at an altitude of nearly 4000 

 feet; it spends the winter as a larva, the first specimens being 

 found by Prof. Steinmann at the end of April, fourteen days 



* Contribution from the Limnologicnl Laboratory of the Department of Ento- 

 mology in Cornell University. 



