AMERICAN ITYMENOPTERA. 89 



Ml'. Walsli's specimens were hivd tVom the galls of A iidrints po- 

 dagra' Walsh, and Baron Osten iSacken's from the galls of Andrlcus 

 eoniigera O. S. 



^»yllcr;;ll!>« iiiediillse Ash. 



Syuenjiis mediilhe Ash., Trnns. Am. Ent. Soc. xii. 1885, p. 302, 9 %■ 

 Syiiergns mediiUie Cresson. Synop. Amer. Hymen. 1887, p. 180. 

 Si/nenjiis meduihe De Dalle Torre, Cat. Hym. ii. 1893. p. 112. 

 " Length .07-. 16 inch., it varying greatly in size. Head and thorax coarsely 



rugoso-punctiite ; antennae 15-.jointed in female, 15-jointed in male, they with 



the head and sides of the collar yellowish ; eyes and thorax brown ; abdomen 



black, smooth and shining: wings hyaline, veins yellow." 



I have four type specimens of this si)ecies sent me by Mr. ^Vsh- 

 mead. There is, evidently, a ty})()graphical error in the original 

 description, for the three females in my possession all have 13-jointed 

 antennae. Like other 13-jointed species the third joint is nearly 

 twice the fourth in length. The sides of the second alxlominal seg- 

 ment are without punctures. 



S[)ecimens of lignicola in my possession, which were also sent me 

 by Mr. Ashmead, and which were bred by him from the galls of 

 A)idvk'H>i cornigera, enable me to separate this species from >nedalke 

 as Ibllows : The parapsidal grooves are much more distinct in ligni- 

 cola than in medulla' ; in the latter species the antenna is very short, 

 hardly reaching beyond the middle of the mesonotum ; in lignicola 

 they are decidedly longer, easily reaching the scutellum, and the 

 terminal joint in the female is unusually long, fully as long as the 

 third. In the males, the last joint scarcely, if at all, exceeds the 

 preceding in medullce, while it is nearly twice the penultimate joint 

 in lignicola. I also notice in my specimens of female medulke that 

 in no case do the ovipositor sheaths project from the second segment, 

 while in lignicola they arc considerably protruded and directed 

 upwards. 



Group II (Anteiuise of female 14-jointed). 

 A. One-third or more of the posterior lateral portion of the second abdominal 

 segment micro.scopically punctured. 

 B. Head and abdomen largelj' yellowish or rufous. 



C. Mesonotum coarsely transversely wrinkled, the wrinkles plainly extend- 

 ing from one parapsidal groove to the other. . .oiieratuiii O. S. 

 CC. Mesonotum very finely transversely wrinkled, the rugai broken between 

 the parapsidal grooves. 

 D. Metiitliorax and pectus black. 



E. Second abdominal segment on tergum, posteriorly, entiiuly hiding 



the following segments garrysina Gill. 



EE. Second abdominal segment on tergum deeply incised, exposing the 

 following segments. 



TR.WS. .\.M. KNT. SOU. XXIII. (12) MARCH, 1896 



