192 Annals Entomological Society of America  [Vol. XIV, 
and situations are found among the species of Pipiza (Note Figures 
12, 16, 17, 20, Plate XI; Fig. 35, Plate XII) and Sphegina (Figs. 69, 
70, 79, Plate XIV) in which species it is usually caudad of the principal 
ramus. 
In spite of the numerous variations there is one general type so 
predominant that it would seem to have some value as indicating 
relationships. I refer to the style that shows a massive, erect, more or 
less pointed or attenuated ramus and from its base on the cephalic side 
a more or less compressed, orbicular lobe that guards the penis at either 
side and that very often is densely spinose on its mesal face. The gen- 
eral type and also something of the endless variations will be evident 
from a study of Figures 4, Plate XV; 83, 84, 88, 89, 92, Plate XVI; 
102. ‘203, 105, 106= 107, 122-and 127) Plate Vil Mo 6 his 20: 
Plate XVIII; and 129, Plate XIX. It is almost the predominant 
condition among Williston’s groups Eristaline and Milesine, and 
almost entirely wanting among the Syrphine. Sometimes this cephalic 
lobe nearly equals or even exceeds in size the caudal lobe as in Figures 
o4 Plate “XVI- 110) 196, Plate XV Ul “and 132, Plate xe Either, 
one of the lobes may bear teeth or hooks or be otherwise modified away 
from the general type as in Figures 87, Plate XVI; 100, Plate XIX; 124, 
Plate XVII. 
Finally in regard to the styles we may note certain very char- 
acteristic types for some of the genera so characteristic that I consider 
them of value in defining the limits of the genus. In Sphaerophoria 
(Figs. 1 and 60 to 66, Plate XV) there are short, very broad, much 
compressed styles, convex laterad, with a more or less rounded, very 
hairy caudal lobe and a more angular cephalic one, often with one or 
two spurs or sharp angles on the mesal face In Pzpiza (Plate XI, 
Figs. 12 to 26) there are erect, slightly compressed, forceps-like styles, 
bowing outward, curving, with an expansion usually toward the caudal 
side at base, slenderest about the middle with the apex expanded and 
typically provided with short, stout, peg-like hairs, about the point of 
contact with the one of the opposite side. In Chilosia (Figs. 27 to 29, 
Plate XII) we find an erect, almost straight style of varying length 
with sharp meso-caudal and meso-cephalic margins, the mesal surface 
between them slightly concave and with short spiny hairs toward its 
apex. Very often on the lateral face toward the caudal side there is a 
ridge or keel, in the more typical species highest basad and usually 
bearing long hairs. 
In Mesogramma (Figs. L, Plate IX; 45, 46, Plate XIII) we note a 
thin, broad, flat somewhat quadrangular style, little specialized. The 
styles, alone, of the genus Platychirus will characterize the genus. They 
are bicornuate, the caudal horn from half as long as to of equal length 
with the cephalic horn; both compressed and convex laterad, and looking 
very much like the thumb and forefinger of one’s partly opened hand. 
In the genus Sericomyia (Figs. 108, 109, Plate XVII) we find a 
condition so peculiar and characteristic that on this basis one would 
feel justified in submerging the weakly characterized Condidea, since it 
has exactly similar styles. The styles are unsymmetrical (see discussion 
