62 MISC. PUBLICATION 17 4, U.S. DEPT. OF AGRICULTURE 



DESCEIPTTON 



Females of Cheiloneurus elegans may be distinguished from all 

 other parasites of Phytophaga destructor by the distinct tuft of stiff 

 erect black hairs on the mostly yellow scutellum. The males are 

 totally unlike the females but may be recognized by their long slender 

 antennae, on each flagellar joint of which are two whorls of long 

 hairs. 



Female. — Length 1.75 to 2.3 mm. Head as broad as thorax, approximately 

 twice as broad as long antero-posteriorly, convexly rounded in front, slightly 

 concave behind ; ocelli in a nearly equilateral triangle ; lateral ocelli close to the 

 eye margins ; fronto-vertex nearly three times as long as broad, its sides nearly 

 parallel ; scrobes short, rounded above ; eyes broadly oval, sparsely clothed with 

 very short pile ; temples very narrow at top of eyes, broadening somewhat be- 

 low ; malar space equal to nearly half the eye height ; mandibles each with three 

 acute teeth ; labial palpi 3-jointed ; maxillary palpi 4- jointed, apical joint 

 as long as the three preceding joints. Viewed from in front the head is sub- 

 triangular in outline, as long as broad ; fronto-vertex, cheeks, and face laterally 

 with fine shallow reticulation, middle of face and area within scrobes nearly 

 smooth. Antennae 11-jointed, clavate, inserted below the eyes ; scape not 

 attaining the front ocellus, fusiform ; pedicel about twice as long as thick 

 and about one and one half times the first funicle joint, the latter a little longer 

 than second, which is the shortest joint ; third very slightly longer than the 

 second ; fourth, fifth, and sixth subequal, each about as long as the first joint 

 but distinctly thicker; club distinctly a little broader than the last funicle 

 joint, and about as long as the three preceding joints, distinctly 3-jointed, not 

 obliquely truncate at apex ; the funicle joints all sparsely clothed with hairs but 

 apparently without elongate sensoria ; club joints with some elongate sensoria. 

 Prothorax short, conical, weakly sculptured ; mesoscutum about twice as broad 

 as long, without grooves, thickly clothed with pale short pubescence, as is also 

 the prothorax posteriorly ; scutellum weakly convex, granularly opaque, about 

 as long as mesoscutum with a tuft of erect long hairs at apex ; axillae meeting 

 on the median line, opaque; propodeum short, polished, without carinae or 

 folds ; pleura weakly sculptured. Wings well developed ; for wing evtending 

 beyond apex of abdomen, about three times as long as broad, with a triangular 

 area extending obliquely caudad and proximad from the stigmal vein and more 

 or less of the base of wing bare; marginal vein nearly half as long as sub- 

 marginal, postmarginal vein shorter than stigmal, the latter about one third the 

 length of marginal; hind wing nearly uniformly ciliated. Middle pair of legs 

 longer than the others, middle tibial spur distinctly longer than first tarsal 

 joint, hind tibiae with one spur. Abdomen nearly as long as head and thorax, 

 as broad as thorax, ovate, depressed above; first tergite comprising about one 

 fourth the length of abdomen, weakly sculptured ; second and third tergites 

 short ; following tergites longer ; ovipositor not exserted. Color of head brown- 

 ish testaceous : the vertex, temples, and cheeks more or less strongly metallic 

 green ; prothorax mostly dark brown, tinged with metallic ; mesoscutum entirely 

 metallic green, covered with pale hairs ; axillae and scutellum brownish yellow, 

 the scutellum with a broad transverse band of paler yellow basally, with a few 

 black hairs scattered over the apical half in addition to the stiff black pencil; 

 propodeum shining metallic ; pleura dark reddish brown with a metallic reflec- 

 tion ; abdomen black with metallic reflections ; fore wings strongly infuscated, 

 the base for most of the length of submarginal vein hyaline, and usually with 

 a subhyaline spot at extreme apex, another on anterior margin just distad of 

 end of venation, and another on the posterior margin a little distad of the 

 one on anterior margin; hind wing hyaline; all coxae pale yellow; the front 

 legs reddish yellow, middle legs also reddish yellow, but with the femora 

 apically and a band on tibiae a little before the base fuscous; hind femora, 

 except at base, and tibiae, except narrowly at base and apex, usually strongly 

 fuscous ; apical joint of all tarsi dark. 



Male. — Length 0.8 to 1.5 mm. Very different from the female. Antenna 

 long, slender, threadlike, 9-jointed (or 10-jointed if a very minute and thin 

 ring joint is counted) ; scape about as long as pedicel and first funicle joint; 

 pedicel about as broad as long; ring joint very thin, strongly transverse, dis- 



