210 R. E. SNODGRASS. 



Each is a large plate, somewhat irregularly triangular in shape, 

 with a large posterior prolongation. 



There are three apical appendages on each side, but the second 

 and third are so united basally that they form one large bilobed 

 structure. The first (fig. 142, A and fig. 143) is comparatively 

 very small and is a simple, fleshy, cylindrical appendage. The sec- 

 ond (figs. 140, 141, 142, B) is a large plate having in side view the 

 form shown in figure 140. It is extended in transverse and perpen- 

 dicular planes from the inner face of the pleurum, and the two form 

 ti double door like covering over the genital chamber. The third 

 or lower most appendage appears like a large ventral lobe of the 

 second (fig. 140). In side view it appears somewhat hood like being 

 curled outward from above and then downward. 



The central vesicle has the typical hemispherical form (figs. 144 

 and 146). The penis does not extend forward beyond the middle of 

 the eighth segment (fig. 149). 



The guard of the penis is a simple, thick structure (fig. 145), 

 grooved above, widened basally and subterminally, ending in a short, 

 thick, tapering prolongation. 



Tipula trivitta Doane (PJ. XVIII, figs. 150, 151, 152, 153). 



The general appearance of the apical end of the abdomen and of 

 the hypopygium is similar to that of Tipula angustipennis. The 

 posterior margin of both the tergum and sternum is notched. From 

 the apex of the notch of the latter there extends forward a narrow 

 membranous area. The pleura are distinct from the sternum, and 

 each is roughly triangular in shape. 



There are only two distinct apical appendages on each side (fig. 

 153). The first (A) has the common elongate, clavate form, and is 

 articulated to the base of the second. The second (B) is a large, 

 flattened, somewhat elongate plate, with the distal end tapering and 

 turned forward, and the anterior margin reflexed outwardly as an 

 elongate lobe, with a free distal end and posterior edge. From the 

 posterior part of the base of the second there projects caudally a 

 small triangular lobe (C), this may be the third appendage. 



The central vesicle is flat; seen in side view (fig. 150, c. v.) it is 

 scarcely convex below. The posterior arms are rather long and 

 slender, and expand distally. From each lateral anterior angle a 

 semi circular flap-like plate extends outward. Between the poste- 

 rior arms is a bar of chitin that corresponds with the Ordinary V- 



