1922] Ciirran: Hammer schmidtia and Brachypoda 243 



genitalia in the male is of great importance and of unusual 

 value in this genus, as has been explained, they are not employed 

 in the descriptions, as it is my belief that they must be demon- 

 strated by means of drawings to be of greatest value, especially 

 when the use of this character is still in its infancy. 



The characters chiefly used are the color of the thorax and 

 abdomen, and it may be safely said that this is sufficiently 

 stable to permit of identification with certainty; and moreover, 

 the structure of the hypopygia bears out the specific limitations 

 in every case where I have males. I am therefore able to state 

 that at present the only species of which there might be any 

 doubt are B. media, flavescens and rufiabdominalis, all of which 

 are closely related to B. bicoJor of Europe. I do, however, 

 believe the ^-pecies mentioned above to be distinct, although 

 one of the American species may be B. bicolor. Dr. Johnson* 

 also remarked upon the constancy of the thoracic lines and 

 abdominal coloration. It -frequently happens that the terminal 

 abdominal segments may appear darkened, but this is due to 

 internal coloration and not to the pigmentation of the chitinous 

 material. 



TABLE OF SPECIES. 



1. Second and third abdominal segments with posterior poUinose bands 2. 



vSecond and third segments without such bands 3. 



2. Thorax with anterior median darker stripes and interrupted sublateral 



stripes; all the abdominal segments with roundish shining spots on each 



side. (Length about /3 mm.) . .cynops Snow. 



fin addition to the stripes as in cynops, the thorax with a roundish spot at 



inner ends of the suture and a slightly oblique stripe on each side 



- posteriorly, second and fourth segments entirely shining anteriorly, 



diver sa Johns. 



3. Abdomen entirely black daeckei Johns. 



Abdomen ferruginous, yellowish, or partly yellow 4. 



4. Last two or three segments shining black; second segment chiefly trans- 



lucent yellowish vacua O. vS. 



Abdomen not so maculated o. 



5. Abdomen with median longitudinal stripe, interrupted before the sutures or 



entire; or arista distinctly plumose 6. 



Abdomen without median longitudinal stripe 8. 



6. Thorax grayish black or slaty; abdomen luteous perplexa Curr. 



Thorax ferruginous or yellowish red 7. 



7. Thorax and abdomen ferruginous (about 10 mm.) gigas Lovett 



Thorax more yellowish red, with lighter stripes; color of abdomen more 



clear yellow (8 mm.) notala O. S. 



8. Thorax reddish yellow; at any rate not at all blackish on the posterior 



half flavescens Shan. 



Thorax blackish 9. 



9. Eyes narrowly separated, most nearly contiguous near the ocelli, 



rufiabdominalis Jones 

 Eyes distinctly contiguous, the vertical triangle long and narrow, .media Will. 



*Can. Ent., Vol. XLIX, p. 361, (1917). 



fThe character of most importance here is the color of the abdomen. Snow's 

 description of thorax was incomplete. 



