2*^ CONNECTICUT GEOL. AND NAT. HIST. SURVEY [Bull. 



ino- connected with the parafacial area). Finally, in the condition 

 which he nicludes under '-holometopie'', the encroaching area of the 

 frontal vitta obliterates the lower portion of each frontal orbit com- 

 pletely, and extends across from one eye to the other, as in Suillia, etc. 

 When the membranous area of the frontal vitta becomes more 

 extensive, sclerotized areas of the head capsule may persist to form 

 sclerotized strips or ''interfrontal strips", which converge anteriorly, 

 as in Desmometopa, ColUnella, Tefhhm, etc. The large ocellar plates' 

 or mterfrontalia, which extend far forward between the frontalia in 

 the Ohloropidae (e. g., Cwpnoptera) are regarded as secondary forma- 

 tions by Hendel. 



Hendel further states that whereas the coronal or sagittal suture 

 bisects the region of the head bearing the ocelli in the Nematocera, in 

 the i3rachycera, on the other hand, what appear to be two branchintr 

 arms, or posterior branches of this suture, demark an ocellar plate, or 

 ocellar triangle, m which the ocelli are situated ; and Hendel makes 

 these designations synonymous with the interfrontalia of Desvoidy's 

 terminology (i. e., the areas extending forward between the frontalia 

 m some flies). Wamwright (1928) calls this area the ocellarium, and 

 both he and Townsend (1908) state that Desvoidv refers to this area 

 (1. e., the ocellar plate) as the "stemmata". It Would appear, how- 

 ever, that Desvoidy probably applied the term stemmata to the ocelli 

 themselves (since this term is frequently used for the ocelli) and ac- 

 cording to Hendel, Desvoidy referred to the ocellar plate as the inter- 

 frontalia. The ocelli are sometimes borne on a raised area or tubercle 

 called the ocellar prominence, to which Wainwright's term ocellarium 

 might well be applied. 



nqn?/^'T"f ^/^^-^?. '^'*'' *^'^* Williston (1908) and Wingate 

 (190b) refer to the ocellar triangle "as being on and surrounded bv 

 the vertical triangle, ' and Walton (1909) indicates that the ocellar 

 triangle may be marked off in the vertical triangle by grooves de- 

 pressions or colorations, although most dipterists do not distinguish 

 between the ocellar triangle and the vertical triangle. In some holop- 

 tic forms m which the ocelli are absent (e. g., in the males of certain 

 iabanidae, etc.) the term vertical triangle is more appropriate than 

 the designation ocellar triangle for the triangular median area pos- 

 terior to the contiguous portions of the eyes, and the former term is 

 so used by most dipterists, while the designation frontal triangle is 

 usually applied to the triangular median'area anterior to the'con- 

 f Sl""fi 1'°''^'°^^^ f,}^''^ eyes (i. e., the area occupying the space be- 

 t^^ een the eyes and the bases of the antennae) . Some dipterists, how- 

 hlln' f^ r ""'' i"'^ ^^'' desio-nation frontal triangle to this area in 

 Hn?^ f .^"f ^^Tl «"^ce Walton (1909) also includes in his defini- 

 tion of the frontal triangle, the "triangle indicated bv color or de- 

 pression in the dichoptic front." Bromley (1926) refers to the verti- 

 cal triangle as the posterior vertex, and refers to the frontal triano-k- 

 as the anterior vertex, in his description of the holoptic male of 

 Tohamts r/^m/./,, although the areas which he calls the anterior and 

 ?b!lT''r'r ^''i ^^'' dichoptic female of this insect appear to be 

 felightlv different from the areas designated bv these names in the 



