28 PEOCEEDINGS OF THE NATIONAL MUSEUM. vol. C3. 



20, METEORUS DIMIDIATUS (Cresson). 



Perilitus dimidiaius Cresson, Canad. Entom., vol. 4, 1872, p. 83. 

 Meteorus dimidiatus Cresson, Cresson, Synops. Hymen. N. Amer., 1887, p. 228. 

 Meteonis noctivagus Viereck, Trans. Kansas Acad. Sci., vol. 19, 1905 (1903- 

 1904), p. 281. 



Type. — In the Philadelphia Academy of Sciences. The type of 

 noctivagus is in the collection of Kansas University. 



This species, while rather easily distinguished, has often been 

 confused with related species. Even in his type series Cresson 

 included, as paratypes, a male of angustipennis and a female of 

 communis, respectively bearing the Nos. 1770.6 and 1770.8. It is 

 most similar to hdkeri, autograpJiae, and vulgaris, and these have 

 frequently been determined as dimidiatus. From halceri it differs 

 principally as noted in the key. The wings are never clear hyaline 

 as in that species, and the ovipositor sheaths are two-thirds to three- 

 fourths the length of the abdomen. Very often the recurrent vein is 

 interstitial with the first intercubitus; othermse it enters the second 

 cubital cell at the extreme basal angle, rarely going into this cell as 

 distinctly as is true of halceri; the lower abscissa of basella is almost 

 always distinctly longer than the upper abscissa, and also longer than 

 the nervellus. From autograpJiae this species can at once be distin- 

 guished by the brown cloud in the stigma, and the shorter antennae; 

 and from vulgaris by the brownish stigma and the more slender 

 ovipositor. The eyes are large, and strongly convergent in the female; 

 consequently the face is narrow; ocell-ocular line usually one and one- 

 half to two times the greatest diameter of an ocellus; antennae 

 normally with 27 to 31 segments; propodeum evenly rugose; first 

 abscissa of radius about half as long as the second; first abdominal 

 tergite polished and without fossae on the petiole, finely ruguloso- 

 striate on postpetiole; thorax usually mostly black, although occa- 

 sionally largely testaceous ; first tergite and apex of abdomen normally 

 black. 



Distribution. — ^Material from the follomng localities has been 

 examined: Numerous points in New Jersey; New York, New Hamp- 

 shire, Vermont, Maine, Massachusetts, Ohio, Illinois, Virginia, Michi- 

 gan, Pennsylvania, District of Columbia, Colorado, Utah, California, 

 Washington, Ontario, and Nova Scotia. The type localitj^ of 

 noctivagus was Lawrence, Kansas. A common species, widely 

 distributed over the United States and Canada. 



Host. — Desmia funeralis Hiibner. Undoubtedly there are other 

 hosts; but collections that I have seen contain almost no reared 

 specimens. J. F. Strauss ^° reported dimidiatus from D. funeralis; 

 this is the only good host record published. Feltia suhgothica 



"U. S. D«pt. Agr. Bull. 419, 1916, pp. 8-9. 



