314 ENTOMOLOGICAL NEWS. [July, '09 



Transverse impression of the face. Also called cheek groove 

 (Townsend). A more or less distinct depression beginning at 

 the ventral end of the arm of the frontal suture, running 

 thence almost horizontally, becoming narrower as it proceeds, 

 under the eye, to the occipital margin thereof. 



Vertex, the top of the head bounded by the eyes, front and 

 occiput. 



Vertical triangle, the triangle on the upper part of the head 

 between the eyes in holoptic flies, it bears the ocelli which may 

 be situated on a triangle indicated by grooves or depressions 

 or colorations, called the ocellar triangle. 



Vibrissae, a pair of stout bristles on the lower end of the 

 facialia, immediately above the peristomium and below the an- 

 tennal foveae on each side, often accompanied by some smaller 

 bristles. 



Vibrissal angles, two prominences at the lower ends of the 

 facial ridges upon which are borne the vibrissae. 



Vibrissal papillae, projections sometimes present at the 

 vibrissal angles. 



Vibrissal ridges, see facialia. 



BRISTLES AND REGIONS OF THE THORAX. 



Acrosticals, posterior and anterior. A row of bristles next 

 to the median line, on the dorsum between the 2 rows of dorso- 

 centrals ; those before the transverse suture are called anterior 

 or preacrosticals : those behind it, posterior or postacrosticals. 



Calypters, a pair of membranous scales situated above the 

 halteres and back of the root of the wing, one above the other. 

 They have been called variously by different authors, tegulae, 

 alulae, squamae or squarnulae, calyptrae, etc. The terms alulae 

 and tegulae are applied to entirely different parts by several 

 writers and are the occasion of confusion in the matter. 



Discal scutellars, see scutellars. 



Dorso-central bristles, on each side, a row on the inner part 

 of the dorsum at the outer side of the acrostical. Those before 

 the transverse suture called anterior, those behind, posterior 

 dorsocentral or postsutural. 



