AMERICAN DIPTERA. 207 



by a high, crest-like fold of membrane (fig. 118, a), except ante- 

 riorly, where they are united by a transverse, arched bar of chitin. 

 A horizontal pleural suture running a short distance forward on the 

 side of the hypopygium (fig. 119, p. s.) is present, the part above it 

 carrying the apical appendages. 



Of the three apical appendages (fig. 122) on each side, the first 

 (A) is the largest. It is flattened and distally is curved posteriorly, 

 and the two form a pair of conspicuous lobes at the apex of the 

 hypopygium (fig. 118). The second (fig. 122, B) has the form of a 

 flat hook with a very wide base and the point turned forward. The 

 third lobe (C) arises from the outer side of the base of the second 

 and overlaps this lobe externally. It has the complicated form 

 shown in the figure. 



The penis curves forward to the anterior part of the seventh ab- 

 dominal segment. The guard is a simple structure composed of two 

 thin, closely appressed blades, set on edge and united by their ven- 

 tral edges. 



Tipula bisetosa Doane (PL XIV, figs. 104, 106, 107). 



The eighth sternum projects beneath the hypopygium. The pos- 

 terior margin is notched. The lateral angles of the emargination 

 are provided each with a long slender hook, from the apex of the 

 notch there arises a wide brush of hairs. 



The tergum of the hypopygium is distinct from the lateral parts 

 of the sternum, and is simply emarginate posteriorly. The lateral 

 parts of the sternum are separated by a rather wide membranous 

 area below. This membrane ends posteriorly in a large fold (fig. 

 106, a). The pleura are not separated from the sternal plates. The 

 pleural region on each side is limited below by a groove running 

 forward a short distance from the posterior rim of the segment (fig. 

 106), and each has its margin produced into a small tapering process. 



There are three apical appendages (fig. 104). The second (B) 

 and third (C) are united basally. The first (A) arises from a slen 

 der peducle lateral of the base of the other two. The first is wide, 

 flat and spatulate. The second is elongate dorso-ventrally, and 

 arises from a short thick stalk at right angles to the rest of it. The 

 third is a triangle with the apex distal. 



The guard of the penis (fig. 107, p. g.) is a short, fusiform struc- 

 ture composed of two blade -like, appressed plates set on edge and 

 having their ventral edges united by membrane. From the sides of 



TRANS. AM. KNT. SOC. XXX. JULY. 1904. 



