THE CrRANE-Fiies or New York — Part II TA7 
The Tipulinae show six lobes in practically all genera, the only exceptions 
being that there are eight in a few rare cases of Tipula and five in Doli- 
chopeza, and that lobes are indistinct or lacking in Tanyptera. 
In the Rhyphidae (Trichocerinae) the spiracular disk is very similar 
to that in many Tipulidae, and is surrounded by four lobes. In the 
Ptychopteridae the very reduced disk is borne at the tip of a slender, 
retractile breathing tube. In the Tanyderidae the condition is somewhat 
similar, but here the disk is larger and is surrounded by five lobes at the 
tip of a long, stout, non-retractile breathing tube. 
The spiracles vary greatly in size from very large to small and vestigial, 
or they may even be lacking in some species of Antocha. They consist 
of an apparently uniform middle piece surrounded by a radially folded 
margin, or ring, of various widths, called the stzgmal ring. Many authors 
(De Meijere, Mik, Miiggenberg, Brown, Keilin, and others) hold that 
the middle piece is an imperforate chitinized plate and that respiration 
takes place thru the stigmal ring. Gerbig (1913), however, shows that 
the middle piece is split across the disk, the cleft being closed by two 
overlapping membranes. Directly behind the spiracles the tracheae 
enlarge into the felt chamber, whose walls are provided with long, branched, 
treelike structures, the branches apparently anastomosing. Surrounding 
the felt chamber in many larvae are dense masses of air tubes, which 
make up the tracheal lungs. These tubes are arranged in bundles, which 
arise in special cavities of the felt chamber; thus, in T7pula paludosa, 
there are about fifty bundles, each of about twenty tubules, making 
a total of one thousand of these air canals (Gerbig). 
_ The early stages of the larva are quite different from the later develop- 
mental stages, as Gerbig (1913:137-140), working on Tipula paludosa, 
has well shown. The prominent six-lobed spiracular disk of the more 
matured larva is represented in the first developmental stage by four 
heavily chitinized projections, which bear but few bristles on their outer 
margin. The dorsal lobes are not evident, but are replaced by eight 
branched bristles, about equidistant from one another. The spiracles 
are oval, not circular as in the grown larva, and project a little beyond 
the level of the disk. The writer has noted several first-stage larvae 
with an appearance almost as described but showing several points of 
difference. The immature larvae of Phalacrocera are described elsewhere 
in this work (page 963). 
