29 



So far as our owa fauna is concerned, the species are too nearly- 

 related to one another, both structurally and also in regard to their 

 habits, to periuit of being separated into smaller groups with any 

 degree of satisfaction. 



TERMS USED IN DESCRIBING TACHINID^E. 



Only a few terms employed in the present work will require an expla- 

 nation, since in most cases the terms used in designating the various 

 l)arts of the specimens are the same as those employed in the other 

 departments of entomolog3^ The term macroch<vt(v is used to desig- 

 nate the stout bristles which arise IVom a convex and usually polished 

 base; ihey are regularly arranged in paii'S, rows, or otherwise, and 

 aftbrd excellent specific and sometimes even generic characters. The 

 frontal bristles are composed of two rows of such macrocha'ta', which 

 descend from the very top of the head to or below the insertion of the 

 aiitennte. The ocellar bristles are composed of a pair of macrocha'ttiB 

 placed among the ocelli, but they are absent in several species. The 

 orbital bristles are two or morepairsofforwardly directed macrocha'tic, 

 situated between the frontal bristles and the eyes; they are usually 

 present in female specimens, and sometimes also in the males. Beneath 

 the anteunai is a cavity known as the facial depression, bounded on 

 the sides by the facial ridf/cs; at the lower ends of the ridges is a 

 pair of macrochietie called the vibrissas The cheeks are between the 

 lower ends of the eyes and the opening of the mouth. The antennce^ 

 as well as their two arista', are always composed of three joints, but 

 sometimes the basal joint is extremely short. 



On the thorax the two rows of macrochieta* in the middle of the 

 dorsum are known as acrostichal, and the uext two rows are the dorsal, 

 although these four rows are sometimes called the dorso-ceutrals; these 

 rows usually extend the entire length of the thorax, those in front of 

 the transverse suture being called the irra^sutural and those behind it 

 the 2)osts'iit lira I; but when the latter term is used in the accompanying 

 l)ages it applies to those in the outer rows only. The row on either 

 side of these four is called the intra-alar; this row sometimes extends 

 in front of the transverse suture by a single macrocha;ta, which has 

 received the name of the jnwsKtural intra-alar bristle. One European 

 author, Mr. Girschner, proposes to separate the Tachinid;c into two 

 groups according to whether this bristle is present or absent, but in 

 some of our species it is present in some sj)eciniens but absent in others 

 that belong to the same species; this character, therefore, is not of 

 siiecific, much less of subfamily, importance. The sternopleural macro- 

 cha'ta' are situated on the upper part of the transverse, more or less 

 triangular, ]»iece located on the sides of the thorax between the front and 

 middle coxa'; when only one is present, this is the posterior; when two, 

 these are the anterior and the posterior; when three, two are in front and 

 one behind; ami when four, these are in a downwardly curving row. 



The macrochictio on the dorsum of the abdomen are called discal 



