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UNITED STATES NATIONAL MUSEUM BULLETIN 224 



medially curved arms of the gonopods, which do not 

 meet, are visible from above if the insect is tilted for- 

 ward and downward, as well as the space which they 

 tend to enclose. The remainder of the true ventral as- 

 pect is hidden under the last tergite. However, viewed 

 from beneath the small, divided and separated epan- 

 drium appears with the tiny proctiger between ; a small 

 inner process appears to arise from the gonopod and to 

 be turned or directed downward. What is presumably 

 the eighth stemite, but may be the eighth tergite, forms 

 a broad, transverse, moderately long or wide band im- 

 mediately in front of the epandrium. The female ter- 

 minalia form a small, short, robust conical projection or 

 protuberance beyond the last tergite; it has a medial 

 dorsal longitudinal fissure. 



Distribution : Neotropical : Eumecosoma calverti Hine 

 (1917); dichroma Bigot (1878); gibbum Curran 

 (1930) ; hirsutum Hermann (1912) ; metallescens 

 Schiner (1868); mollis Bromley (1934); pleuritica 

 Wiedemann (1828); shropshirei Curran (1930); 

 staurophora Schiner (1868) ; tarsalis Curran (1930). 



Catonomyia, new genus 

 Figure 660 



Type of genus: Catonomyia spiculata, new species. 



Small, slender, black flies with punctulate abdomen 

 but smooth mesonotum. The scutellum has a pair of 

 long, spikelike bristles. The slender hind femur bears 

 only long, quite slender bristles of which there are 2 

 laterally, 2 basally and ventrally and 2 or 3 other fine, 

 long hairs and a ventral fringe of erect, fine hairs. 

 Third antennal segment angulate below near the base, 

 the lower margin thinned, the apex with a microsegment 

 and basal spine. Length 7 mm. 



Head, lateral aspect: The face is quite plane with 

 the eye except for a very short, small elevation on the 

 lower fourth of the face. Occiput poorly developed, 

 more prominent submedially ; it is completely recessive 

 on the upper fifth of the head. The occiput bears a 

 few, fine, scattered hairs on the lower half, 3 weak 

 bristles above, and 4 more stout, black bristles behind 

 the upper vertex and upper eye corners. Proboscis 

 small with truncate apex bearing fine, bristly hairs. It 

 does not extend beyond the face. Palpus quite minute, 

 short, cylindrical with 3 slender, apical, bristly hairs; 

 the basal segment is very short. Antenna attached at 

 the upper fourth of the head, in profile, but actually 

 almost at the vertex. The first segment is slightly 

 longer than the second and both are short and both 

 bear fine setae above and below. The first segment 

 bears 1 long, slender bristle and 1 short bristle attached 

 ventrally in the middle. Third segment, microsegment 

 included, is a little more than twice the length of the 

 first two together and narrow at the base ; it is rapidly 

 widened and close to the base the ventral surface is 

 angulate and from there to the apex thinned and also 

 reduced in thickness. The apex bears a short, more 

 narrow, obtuse microsegment carrying a distinct, sub- 

 basal, dorsal spine. 



Head, anterior aspect : The width of the head is ap- 

 proximately 11/2 times the height. The face below the 

 antenna is quite narrow and becomes more narrow in 

 the middle and slightly wider below. In the middle 

 the width of the face is from a seventh to an eighth the 

 head width, its surface densely, finely micropubescent. 

 It bears on each side vertically 5 or 6 fine, slender, pale 

 hairs. On the small gibbosity above there are 2 slender, 

 black bristles followed by 3 longer, equally slender, 

 yellow bristles in a vertical row on each side. Front 

 and vertex strongly widened ; the vertex is rather deeply 

 excavated; the small, high ocellarium has nearly ver- 

 tical sides and between the ocelli there is a pair of erect, 

 moderately strong, long bristles; behind the ocelli 2 

 small hairs. Front with a median ridge ; the sides have 

 3 or 4 weak hairs. 



Thorax : The thorax is comparatively short and mod- 

 erately high but not on the mesonotum. The mesonotum 

 is gently convex with an abrupt, overhanging, posterior 

 margin leaving a basal crease beneath it ; the anterior 

 margin is also abrupt. Surface densely covered with 

 fine, suberect pile. The lateral bristles are mostly 

 slender and consist of 1 notopleural bristle, 1 or 2 supra- 

 alar, 1 on the postalar callosity, and on the scutellum 

 a pair of quite long, conspicuous, basally stout, attenu- 

 ate, spikelike bristles. Metanotum high and laterally 

 with a tuft of stiff pile. Pronotum with only weak 

 hairs. Posterior dorsal corner of mesonotum, however, 

 with a long, conspicuous bristle. Metapleuron with a 

 vertical row containing 4 dorsal, black and 3 ventral, 

 yellow bristles, very long, curved distally. Postmeta- 

 coxal area with wide, complete arch of chitin. Pro- 

 sternum fused laterally. 



Legs: All the femora are slender, the hind pair is 

 very slightly widened before the apex. They bear fine, 

 scattered, more or less appressed pile. The posterior 

 femur is plane on its lower surface and bears a mod- 

 erately dense fringe of fine, erect, ventromedial pile. 

 It has 2 slender, long, fine bristles in the middle laterally, 

 2 other longer bristles on the basal third ventrally ; it 

 also has a few long, bristly hairs ventrally and ventro- 

 medially. Hind tibia short, slender, with a similar fine, 

 medial fringe changing to ranked setae distally and 

 with 2 conspicuous, long, basally stout bristles near the 

 middle ; it has 4 or 5 other more slender bristles ventrally 

 and 3 fine, bristly hairs dorsomedially. Tarsal segments 

 slender and elongate. Middle femur with more slender 

 bristles and weaker ones. There is an anterodorsal 

 bristle beyond the middle, near it an anterior bristle, 

 and at most a bristly hair posterodorsally near the apex. 

 The very slender middle tibia bears 3 conspicuous, ex- 

 ceptionally long, basally stout, anterodorsal bristles, 2 

 almost equally conspicuous, equally long, ventral bristles 

 on the basal half, 1 near the apex, and 3 much smaller, 

 fine, dorsal bristles distributed at equal intervals. An- 

 terior femur with only a few, fine, bristly hairs. The 

 anterior tibia has 3 weak, slender, dorsal bristles, 3 quite 

 long bristles more stout at the base, located posteriorly 

 and 2 similar, ventral bristles. Tarsal segments ex- 

 ceptionally slender and long with remarkably long, 



