CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 269 



C. Last section of fourth vein (Mi^.2) with a rounded angle. — 

 Musca. 

 CC. Last section of fourth vein curved forward, often slightly, beyond 



/ d.dc anterior dorso centrals 

 aide •■ inner - 

 a. ia ■■ intraalar 

 h liumerals 

 p.h post " 

 * '\ps. presutural 

 Scute Hum hdc posterior dorso centrals 

 yp.ldc ■• inner •• 

 i.a. intraalar 

 pra prealar = anterior sa 

 sa supra alar 

 -.. sq. \ -( Lower squamar 

 \jj isq.\ \ ^^'\squamula thoracal is 



■ ^ \5quamula a/aris 



Vertical 

 -Ocelli 



prbitals 



>./) 



2/4,.. 



}.^-- 



./^53, 



■Ocellar 



Antenna 

 r^lil^^-Vibrissal ndges 

 Oralmargin 



Vibrissa 

 ^Palpus 

 Proboscis 



Fig. 171. — Dorsal aspects of the thorax, and frontal aspect of the head of a 

 muscoidean fly, with designations of the parts commonly used in taxonomic work. 

 {After Riley and Johannsen, Comstock Pub. Co., Ithaca, N. Y.) 



its middle or at the tip, the cell broadly open; the first longitudinal 

 vein (Ri) ending beyond the middle of the wing. — Muscina. 

 BBB. Arista plumose; hypopleurae and eyes as in B; vibrissal angle, near 

 oral margin. 



