210 
6. 
10. 
1B, 
THE BLOWFLIES OF NortH AMERICA 
Tubercles bordering stigmal field not prominent; inward 
projection of peritreme between outer and middle slits 
of posterior spiracles absent or at least not prominent; 
anterior spiracles generally with from 5 to 7 branches. . 
Tubercles bordering stigmal field large; the spiracular 
plate heavily pigmented, large, and with a prominent 
inward projection between the outer and middle slits; 
anterior spiracles generally with from 7 to 10 branches. 
aia Sa A os i Phaenicia caeruleiviridis (Macquart), p. 235 
. Posterior margin of segments 9 and 10 without dorsal 
spines and the posterior margin of segment 11 with 
three or four irregular rows of dorsal spines; peritreme 
between outer and median spiracular slits not projecting 
IT Weld eee Phaenicia pallescens (Shannon), p. 251 
Posterior margins of segments 9 to 12 completely encircled 
with spines, and segment 11 with six to eight rows of 
dorsal spines on posterior margin; peritreme between 
outer and median spiracular slits projecting inward.... 
ae ey > Bufolucila silvarum (Meigen), p. 222 
. Labial selerite with width of basal portion and length of 
entire sclerite subequal, the apical tooth-like portion 
S110) deh ee ee EIEN 
Labial sclerite longer than broad, the apical tooth-like 
portion usually much longer than the entire width of 
basal portion... es... fe en tl. eben fee 10 
. Labial sclerite with length of basal portion less than length 
of apical tooth-like portion... 03. . 02>... 
oy a wore ft een ae Cyanus elongata (Hough), p. 333 
Labial sclerite with length of apical tooth-like portion as 
long or only slightly longer than length of basal portion 
SANTIS AEE Solan AES Eucalliphora lilaea (Walker), p. 286 
Segment 9 bare anterodorsally.......0.......s: ee Bi 
Segments 2 to 9 spinose anterodorsally................ 12 
Spines small and lightly pigmented; tubercles on both 
dorsal and ventral margins of anal area nearly equi- 
distant; anal protuberance with only a few lightly 
pigmented spines Calliphora coloradensis Hough, p. 296 
Spines large and deeply pigmented; median and inner 
- tubercles on dorsal surface and median and outer 
tubercles on ventral surface of anal area approximated; 
anal protuberance with numerous pigmented spines. . 
<4 2 keds GS ce et Calliphora lida Hall, p. 299 
