164 Annals Entomological Society of America [Vol. VII, 
The squamopleura exhibits characters in connection with 
the hypopleura and the posterior thoracic spiracle which are 
at times of importance. It therefore requires a special designa- 
tion though it is not apparently a separate sclerite. It is 
sometimes bare, often pilose or hairy, sometimes bristly, while 
the position of the spiracle with reference to it and the hypo- 
pleura may be used in the separation of groups among the 
connectant forms. 
Higher Posterior thoracic spiracle behind vertical axis of squamopleura 
and Typical and hypopleura—Musca, bulk of Muscoidea, Leucomelina, 
Muscoidea Limnophora, Spilogaster, Gen. Indet., Fannia. 
Anthomyioidea {Posterior thoracic spiracle squarely interposed between the 
Connectant | squamopleura and hypopleura—Muscina, Synthesiomyia, 
Muscoidea Morellia, Aricia (last judged from figures). 
VENATION 
Fourth vein when complete or apical crossvein when present 
reaching margin at or before extreme wingtip, the hind cross- 
vein always joining fourth vein well before bend of latter or 
origin of apical crossvein—Musca, bulk of Muscoidea, but 
Higher and including only Cobboldia among the Oestride and allies. 
Typical {Fourth vein always complete and reaching margin before wingtip, 
Muscoidea | the apical cross-vein not present, the hind cross-vein prac- 
tically in line with the last section of the fourth vein—Glossina, 
Cuterebrida, Hypodermine, Oestrine. 
Fourth vein incomplete, not reaching wing margin; apical and 
hind cross-veins obsolete—Gastrophilus. 
Fourth vein always complete, reaching margin behind extreme 
wingtip, always bowed forward apically; no apical crossvein— 
Connectant Stomoxys, Haematobia, Lyperosis, Hypodermodes, Eumesem- 
Muscoidea brina, Muscina, Myospila, Clinopera, Pararicia, Leucomelina; 
the last three with least forward bow to fourth vein and thus 
{ most approaching the anthomyioid type. 
Fourth vein not bowed forward in any part of its extent, but 
Anthomyioidea ; often bowed backward apically—Limnophora, Spilogaster, 
Fannia and other Anthomyioidea. 


Of the above Haematobia furnishes an aberrant form of the 
Stomoxys type, and Glossina an aberrant form of the Musca 
type. Only Clinopera, Pararicia and Leucomelina are inter- 
mediate between the Stomoxys and Anthomyia types. A 
number of forms are intermediate between the Stomoxys and 
Musca types. 
