AUTlS DIPTEKA OR TWO-WINGED FLIES ALDRICH 35 



The species is strictly congeneric with Dexia rustica Fabricius of 

 Europe, type of the genns. It agrees very well with the description 

 of Dexia divergens Walker, described from Mount Ophir ^ ; but one 

 of our specimens was compared with Walker's type in the British 

 Museum by Dr. J. D. Tothill and showed differences apparently 

 specific. 



Genus EUTRIXOPSIS Townsend 



Eutrixopsis Townsend, Insecutor In.scitiae Menst., vol. G, p. 166, 1918. 



This genus was based upon the single species javana, described 

 by Townsend on the same page ; only a single specimen was known, 

 a male from JaA-a. The species has recently been found by Clausen 

 and King, of the United States Bureau of Entomology, to be an 

 important parasite of the " Japanese Beetle," Popillia japonica 

 Newm., in Japan. Their studies of its biology and economic rela- 

 tions will be published elsewhere. 



The genus differs from Eutrixa (inclusive of Eutrixoides Walton) 

 chiefly in having mucli narrower parafacials and broader and flatter 

 facial ridges: in other Avorcls, the suture encloses a much broader 

 portion of the head below. The parafacial also bears close to the 

 eye a more or less double row of hairs. Both genera are parasitic 

 on melolonthine beetles in the adult stage. 



Since javana has been only briefly described hitherto, its eco- 

 nomic importance requires that it be given a full description here. 



EUTRIXOPSIS JAVANA Townsend 



Eutrixopsis javaiHi Townsend, Insecutor lascitiae Menst., vol. 6, p. 166, 

 1918. 



Male. — A brown fly with mostly yellow abdomen and legs. Eyes 

 almost contiguous on the front, separated by less than the width of 

 the anterior ocellus, ocellar triangle small, elevated ; ocellar and ver- 

 tical bristles absent, no hairs on front above middle, a few small 

 bristles below stopping short of the lunule; small hairs begin on 

 lower parafrontais and continue down the narrow parafacials in a 

 mostly double row to the lower end of the lunule. Antennae brown, 

 very small, third joint twice the second, arista pale, about three 

 times as long as the third joint, bare, its penultimate joint short. 

 Facial ridges flat, converging below and at the closest point sepa- 

 rated by hardly more than the width of the third antennal joint. No 

 vibrissae, the ridges hairy in this region and bearing a few small 

 but increasing bristles toward the mouth, which is some distance 

 below. Palpi and proboscis ordinary, the former yellow. Back of 

 head concave above, convex below. Bucca half the eye height, the 



eProc. Linn. Soc. vol. 1, 1856, p. 21. 



