292 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 90 



one-half the length of third ; paraf acialia at narrowest part compared 

 with distance between vibrissae as 11.0 : 19.8 (average of six) ; cheeks 

 one-third or more of eye height. 



Thirty-five other males, with the essential characters of the cotype, 

 show a slight variation. In all but two specimens, in which there were 

 three on one side, there were four dorsocentrals ; the posterior preintra- 

 alar bristle was usually strong but sometimes only a hair. Twenty- 

 nine specimens had the second genital segment black, tinged with red 

 above and wholly red beneath. In the others it was either wholly red 

 or black above. Thirty-two flies had the second antennal segment 

 reddish or reddish brown and in three it was black, tinged with red. 

 Thirty-three had the facial ridges bristly for two-thirds their way and 

 in two on the lowest third. Length, 10-16 mm. 



Female. — Front at vertex 0.37 and 0.36 of the head width in 

 two specimens; paraf rontalia lightly golden pollinose, sparsely be- 

 set with pale hairs; inner and outer verticals developed; orbitals 

 strong; frontals nine in number, strong; paraf acialia silvery polli- 

 nose with slight golden cast, at narrowest part compared Avith dis- 

 tance between vibrissae as 9.5:18.5 (average of two); cheeks one- 

 third of eye height ; second antennal segment mostly black, about one- 

 half length of third; thorax black, grayish pollinose with brownish 

 tinge above, pleurae more grayish ; four dorsocentrals ; posterior pre- 

 intraalar bristle present; abdomen black, intermediate segments 

 grayish pollinose with trace of brown, particularly at apices; last 

 segment wholly chalky white pollinose. Abdominal macrochaetae 

 as follows: One fly has a median pair on the basisegment; otherwise 

 the first and second segments each has one marginal pair ; third with a 

 marginal row; fourth with a row of discal or submarginal onas 

 besides the marginal row of moderately long bristles of unequal 

 length. 



Remarks. — The foregoing description of the female of panaetius 

 is from two specimens captured in coitu at Melrose Highlands, Mass., 

 in May 1934. Other descriptions of the female of Tachinomyia 

 panaetius have been given by Townsend (1915, p. 103) and Curran 

 (1926, p. 169). 



Material examined. — At the United States National Museum there 

 are 62 males from various localities in the United States and Canada 

 east of the Rocky Mountains. There do not appear to be any speci- 

 mens from the Southern or Southwestern States. Six males and 

 two females of the Melrose Highlands laboratory collection are from 

 Massachusetts and New Jersey localities. 



Hosts. — The writer has not seen any bred specimens that could 

 be positively identified as panaetius. There are, however, in the 



