ART. 17. NORTH AMERICAN PHOROCKRA JU.DRICH AND WEBBER. 9 



excluded a considerable portion of his material; it differs also from 

 that of his Type Species paper of 1910, in which he divided the 

 group in the European manner, following Professor Bezzi's Palae- 

 arctic Catalogue. Doctor Townsend has never published a synopsis 

 of the group now under consideration, but it is apparent from his 

 papers that he would recognize a large number of genera. 



The latest European treatment is by Baer,- whose table can be 

 reduced for the present group to the following : 



1. Hind tibiae ciliated on outer side, at least in male, with I'egular comb- 



like curved bristles, among which one or two sometimes stand out 



larger Carcelia. 



Hind tibiae with unequal bristles, bare or less regularly bristled 'J. 



2. Apical scutellars erect and decussate; claws in both sexes short Phryxe. 



Apical scutellars generally curved backward, decussate or convergent ; 



sometimes feebly developed; rarely erect, and then the male has long 

 claws 'S 



3. Facial ridges with somewhat regularly arranged bristles above the vi- 



brissae to the middle of the eye height ; cla\A's of male elongate Zenillia. 



Facial ridges with only a ,few rapidly decreasing bristles above the 

 vibrissae; bucca not over one-fourth the eyeheight Exorista. 



The first character of this table is perhaps the most difficult of 

 all to apply to the North American material. It is better developed 

 in males than females, and there are numerous intermediate species. 

 We are unable to see more than a specific character in the apical 

 scutellare, and the length of the claws in the male seems of even 

 less importance, as it is confined to one sex. 



We are unable to make an abridgement of Brauer and Bergen- 

 stamm's tables ^ which will show their disposition of this group. 

 Wliatever merit these authors possess is not to be found in their 

 construction of analytical tables. It would seem that in the course 

 of their work they modified their tables a little at a time, until in 

 their final form they are very complicated and confusing. 



The type species of Zenillia, libatrix Panzer, does not occur in 

 North America. It has yellow pollen dorsally on head, thorax, and 

 abdomen, about as in our helvina Coquillett, with which it also agrees 

 in having three sternopleurals, four dorsocentrals, two bristles on tlie 

 front side of the middle tibia, etc. ; but diffei-s in having large discals 

 on the second and third segments {helvina has small on the third 

 only), and especially in having the facial ridges bristly almost to 

 the middle, so as to come rather close to Phorocera in this character. 

 The bristles, however, are weak, hardly more than hairs, and do not 

 extend quite so high as in Phorocera. 



a Die Tachinen als Schmarot;5er der schildlicberv Insekten, Beiheft Ztschr. f. angewandte 

 Ent, p. 75, 1921. 



sZweiflilgler dps kaiserlichen Museums zu Wien, parts 4 and 6, 1889 and 1893. 



