Earlier Stages of Cylindrotomina. 365 
Nachr. 1878, p. 5), contains the following state- 
ment :—“'The three-fold branches of the thorn- 
like processes (die dreifach veriistelten Dornen) of 
the larva of De Rossi, remind one of the aquatic 
larva described by De Geer, and as this new larva 
seems to hold the middle place between the 
terrestrial larva of Cylindrotoma and the aquatic 
one of De Geer, it seems to me possible and even 
probable, that it may belong to a third of the 
known genera of the Section Cylindrotomina, 
Triogma. This supposition seems to be supported 
by the fact that this larva, like the aquatic larva 
of Phalacrocera, feeds upon a species of moss 
(Hypnum), differing in this from the larva of 
Cylindrotoma, which, as we have seen, occurs on 
different kinds of phanerogamous plants.” 
In the Monograph of North American Diptera, iv., 
pp. 289-292, I have shown that the Cylindrotomina 
occupy an intermediate position between the two great, 
and otherwise very well defined, divisions of the Tipulide, 
the longipalpi and brevipalpi. And I have called atten- 
tion (1. c. p. 295) to the anomalous character of their 
larvee, corresponding with that of the perfect insects. 
Larve climbing upon living plants, feeding upon them, 
and gnawing holes in their leaves, are toto clo different 
from ordinary larvee of Tipulide. These larvee must of 
course show corresponding adaptations for such a mode 
of life, and it will be the task of future investigators to 
describe these structural differences in detail. What we 
can gather from the existing descriptions is very little, and 
is found principally in Zeller. According to him, climb- 
ing is made possible by sucking-cups, the principal one of 
which is produced by the withdrawal of the head into the 
thoracic segments, thus forming a hollow, the edges of 
which complete the cup. He believes that eight pairs of 
conical, fleshy protuberances on the ventral side when 
withdrawn, may likewise act as sucking-cups for loco- 
motion. Zeller’s statement about the breathing apparatus 
proves that the larve of Cylindrotoma distinctissima are 
metapneustic, like those of Phalacrocera and other Tipu- 
TRANS. ENT. Soc. LOND. 1897.—PparT Iv. (pEc.) 25 
