80 PROCEEDINGS ENTOMOLOGICAL SOCIETY 



described Mesidia pwnila in the third number of his Hymenop- 

 terological Miscellanies from a specimen taken by Doctor Foer- 

 ster, and this may have been the type of the genus for all we know 

 to the contrary. Mayr does not mention whether the club of 

 the antenna is solid or is jointed. Ashmead, in his Classification 

 of the Chalcid Flies, assumes that it is solid and gives the antennae 

 of Mesidia as six-jointed. In Technical Series No. 12, part IV, 

 New Genera and Species of Aphelininse, the writer described 

 Mesidia mexicana n. sp., and erroneously, in his table of genera, 

 stated that* the antennae are seven-jointed; the same error was 

 perpetuated in the figure. Reexamination of the type shows that 

 the antennae are really eight-jointed, the club being distinctly 

 three-jointed. 



The matter now becomes complicated from the finding of a 

 single slide of a Mesidia-like form bred by Prof. C. P. Gillette at 

 Fort Collins, Colorado, from Brachycolus tritici, which possesses 

 all of the characters of Mesidia with the exception that the club 

 is solid. 



Inasmuch as Mayr did not state in so many words that the an- 

 tennal club of M. pwnila is solid, although the presumption would 

 be in favor of solidity, the writer by letter begged his friend, 

 Dr. Anton Handlirsch of the Vienna Museum, to which insti- 

 tution Mayr's collection went after his lamented death, to examine 

 the type, with the result that Handlirsch found the club to be 

 solid. Therefore the species named by Gillette is a true Mesidia 

 (and is described below), while the writer's Mesidia mexicana 

 becomes the type of a new genus which is also here described under 

 the nam'e Dirphys. 



Mesidia gillettei n. sp. 



Female: Length 1.02 mm. ; expanse 2.77 mm. ; greatest width of fore-wing 

 0.44 mm. General color dull honey-yellow, legs and antennae concolorous 

 with body or perhaps a little lighter, the 2 terminal tarsal sclerites of each 

 leg darker. Pedicel and first and second funicle joints subequal in length, 

 third funicle joint somewhat shorter; club about as long as second and 

 third funicle joints together, somewhat laterally pointed at apex when seen 

 at side; eyes hairy. Wings broad, veins distinctly honey-yellow, stigmal 

 vein very short; oblique hairless streak broad and distinct, widening some- 

 what towards base. Abdomen ovate, a trifle broader than thorax and about 

 as long; ovipositor not exserted. 



Male: Unknown. 



Type: No. 18322, U. S. N. M. 



Described from a single female reared by C. P. Gillette, October 

 13, 1908, from Brachycolus tritici, presumably at Fort Collins, 

 Colorado. 



