ROBBER FLIES OF THE WORLD 



581 



is tlie principal one separating the genus from Neomoc- 

 therus Osten Sacken and Cerdistus Loew, which like- 

 wise has a very poorly produced face. It is the simi- 

 larity of the face wliich has produced much confusion 

 and caused many authors to place the species of Neo- 

 mocthenis and sometimes other genera indiscriminately 

 into II eligmonexira. It has not been generally realized 

 that Heligmoneura is closely related to an Oriental 

 complex of genera, namely Cinadus Wulp, Oligoschema 

 Becker and to a lesser extent Orophotus Becker. In 

 Heligmoneura the superior forceps are characteristi- 

 cally cleft in a deep and peculiar fashion; the halves 

 are widely separated and in coiisequence the genital 

 cavity is large and open. The gonopod is quite small 

 and tends to be enclosed by the overly developed for- 

 ceps. Claspers are present and borne by the gonopod, 

 as well as stiletto-like paralobi borne by the superior 

 forceps. Length 10 to 20 mm. 



Head, lateral aspect : The head is of medium length 

 and the face quite short, very slightly produced below; 

 most of the lower face is visible because of the recession 

 of the eye. The occiput is short and the lower fifth of 

 the eye recessive posteroventrally. The occipital pile is 

 very fine, dense and of moderate length ; weak bristles 

 begin above the middle and there are 3 or 4 pairs of 

 stout bristles behind each upper eye corner, together 

 with 1 deep, postvertical bristle. The proboscis is 

 slender, extending well beyond the face and pointed 

 at the apex ; the palpus is slender and of one segment, 

 with fine, stiff hairs at the apex and below. The an- 

 tenna is attached at the upper third of the head or just 

 below it and, together with the style, is about as long 

 as the head. The first segment is nearly twice the 

 length of the second. The third segment is a little 

 longer than the second, slender, flattened, without 

 microsegment and with a rather long, slender style 

 which, at the slightly thickened apex, bears a bristle-tip. 



Head, anterior aspect: The face below the antenna 

 is narrow, about one-seventh the head width or less; 

 the whole face is finely pubescent, generally witliout 

 ! pile or bristles on the upper half and with numerous, 

 long, slender bristles on the ventral half, continued 

 down much of the lateral margin of the deep, concave, 

 oblique, pubescent subepistoma; cheeks short. The 

 front is small, pollinose, flat, with a conspicuous sub- 

 ocular row of 4 bristles and above it an ocular row of 

 3 bristles. The front is slightly divergent and more 

 strongly convergent at the vertex; the vertex is mod- 

 erately excavated, the ocellarium low with a pair of 

 bristles or bristly hairs between the posterior oceUi and 

 2 other pairs behind. 



Thorax: The mesonotimi is moderately high, polli- 

 nose and abrupt both posteriorly and anteriorly though 

 strongly rounded; it has abundant, very fine, nearly 

 erect, bristly pile. There is a double acrostical row of 

 poorly differentiated bristles. There are weak dorso- 

 central, bristly hairs behind the humerus, longer and 

 slender posteriorly, beginning opposite the transverse 

 suture. Humerus with fine pile. The lateral comple- 

 ment of long, moderately stout, sharp bristles consists 



of 2 notopleural, 1 supraalar, 1 suprapostalar, 2 posta- 

 lar and 1 scutellar pair. The convex scutellum, with 

 impressed rim, is pollinose, with about 12 fine, erect 

 hairs. Metanotal callosity bullose, creased behmd and 

 with stiff hairs. Pronotura with few bristles. The 

 propleuron, upper mesopleuron, stemopleuron and 

 pteropleuron each have a few, fine, long haii"S. Both 

 anterior and posterior basalare with a few, fine, bristly 

 hairs. Posthypopleuron and metapleuron each with 1 

 or more distinct bristles and some bristly pile. Post- 

 metacoxal area membranous; prosternum fused. 



Legs: The legs are rather slender; the first four 

 femora very slightly swollen towards the base, the 

 slightly elongate hind pair barely widened distally and 

 together with the tibiae bear loose, fine, subappressed 

 setae. Bristles are attenuate, only moderately stout 

 and numerous. The hind femur bears 3 lateral, 1 ven- 

 trolateral near the apex, 3 or 4 prominent, medial 

 bristles on the outer half, and 4 or 5 ventromedial 

 bristles on the basal half; dorsomedial apex with 1 

 bristle. The middle femur has 3 prominent, anterior 

 bristles and 2 anteroventral along the middle, besides 1 

 posterior bristle at the apex. Hind tibia with 3 dorso- 

 lateral, 1 or 2 dorsomedial, and 3 ventrolateral bristles; 

 apex with 6 bristles. Hind trochanter and all the coxae 

 laterally with stout bristles. The anterior femur in 

 males has 4 or 5 slender, posteroventral bristles, and a 

 posterodorsal fringe of long, bristly hairs, absent in 

 the female. Females, however, have 3 or 4 stout, ventral 

 bristles on the basal half usually. The middle and 

 anterior tibiae have bristles similar to the hind pair 

 but the posterior and posteroventral bristles are much 

 longer. Basitarsus nearly as long or quite as long as 

 the next three segments; their bristles are accentuated 

 especially posteriorly. Claws slender, sharp, bent at 

 apex ; pulvilli and empodivmi long. 



Wings: The marginal cell in the males and females 

 a little widened, but not at the expense of the subcostal 

 cell ; at most faintly rippled. The posterior branch of 

 the third vein beyond the fork of the third vein is sinu- 

 ous. Base of second posterior cell rather abruptly wid- 

 ened, but not twice the width of the discal cell. Fourth 

 posterior and anal cells closed and stalked ; alula large ; 

 ambient vein complete. 



Abdomen: The abdomen is comparatively slender; 

 the first two tergites nearly or quite as wide as the 

 mesonotum. The abdomen is subcylindrical, a little 

 tapered and about as long as the wing. The pile is 

 rather scanty, fine and appressed. All the tergites lat- 

 erally bear distinct bristles near their posterior margin. 

 The JDasal sternites have fine pile ; the third sternite may 

 have a few, weak bristles. Males with seven tergites 

 and the eighth very short. Females with seven tergites, 

 those beyond forming the ovipositor. Male terminalia 

 has the superior forceps grossly enlarged in various 

 shapes, rather short and clublike; frequently with a 

 deep excision, which leaves terminal prongs. The ter- 

 minalia are not rotate ; the aedeagus is formed in three 

 primary parts. The very short gonopod is concealed 

 within the interior. The hypandrium is very short or 



