ART. 15«. REVISION OF SUBFAMILY PLATYGASTERIXAE FOUTS. 115 



In these two forms, mucronata and howardii we have extreme elon- 

 gation of the tail of the abdomen. In no other described species 

 from North America does the tail of the abdomen equal in length 

 the body anterior to its base. 



Some of the characters described above are not constant. It seems 

 that the proportion of the last segment to the three preceding is rather 

 fixed, but the length of this segment in proportion to its width varies 

 greatl}^, the segment being in some instances a little over five times, 

 and in others slightly more than six and one-half times as long as 

 wide. The two paratypes which have the former proportion are also 

 shorter in their entire length than the paratype with the more elon- 

 gate sixth segment. The smaller specimens measure 1.5 mm. from 

 the front of head to the tip of the sixth segment. The type and the 

 remaining paratype are of about the same size and proportion as the 

 arger paratype mentioned above. 



SPECIES OF UNCERTAIN POSITIOIl. 

 SACTOGASTER VARIPES Harrington. 



Sactogaster varipes Harrington, Trans. Royal Soc. Canada, vol. 5, 1900, p. 190. 

 The original description is as follows: 



Female. — Length 0.7 mm. Black microscopically punctate. Legs piceous, base 

 of tibiae and tarsi yellowish. Scape of antennae pale. Scutellum with sharp awl- 

 like spine; sides of metathorax and base of abdomenwith silvery pubescence. Termi- 

 nal segments of abdomen forming deflexed tail, which is shorter than second segment; 

 second segment polished, terminal segment finelj^ punctulate. 



Male. — Closely resembles female except in shape of abdomen and antennae. 



Described from one female and one male taken in August, Hull. The female very 

 closely resembles S. anonialiventris, except in the shape of the second ventral seg- 

 ment which is much flatter. 



Descriptions must be particularly accurate in this group to be of 

 any value in identification. The one just quoted is not of much use. 



XL Genus LEPTACIS Foerster. 



Leptacis Foerster, Hym. Stud., Heft 2, 1856, pp. 107, 112 (four species). Gen- 

 otype. — Platygaster tipxhJae Kirby. (By original designation.! 



Ectadius Foerster, Hym. Stud., Heft 2, 1856, pp. 108, 113, 144. (Monobasic.) 

 Genotype. — Platygaster craterus Walker. (By original designation. ) 



Synopeas Foerster, Hym. Stud., Heft 2, 1856, pp. 108, 114 (sixteen species). 

 Genotype. — Platygaster sosis Walker. (By original designation.) 



Avopedias Foerster, Hym. Stud., Heft 2, 1856, pp. 108, 114. No species 

 originally included. 



Ceratacis Thomson, Ofvers Svensk. Vet.-Akad. Forh., Heft 16, 1859, pp. 

 69,78. (Monobasic.) Genotype. — Ceratacis flavi pes Thomson. (By original 

 designation.) 



Dolichotrypes Crawford and Bradley. Proc. Ent. Soc. Wash., vol. 13, 1911. 

 p. 124. (Monobasic.) Genotype. — Dolichotrypes hopkinsi Crawford and Brad- 

 ley. (By original designation.) 



