DASTPOGONINAE 



ROBBER FLIES OF THE WORLD 



241 



Genus Lastauroides Carrera 



Figures 545, 1074, 1083 



Lastauroides Carrera, Arq. Zool. Sao Paulo, vol. 7, p. 94, 1949. 

 Type of genus : Lastauroides alcxanderi Carrera, 1949, by 

 original designation. 



The following is Carrera's description in translation: 



Head : Pace plane toward the top, always with a small sali- 

 ence in the buccal border. Mystax formed by long bristles 

 located in the oral margin. Ocellar salience with a tuft of 

 variable bristles. Front with abundant pile along the sides 

 and at the vertex. Proboscis with a dorsal ridge and slightly 

 inclined downward. The palpus forms an angle with the 

 junction of the two segments, but with exceptions, continuous. 

 Third segment of the antenna at base and at apex somewhat 

 more slender and rarely longer than two times the length of 

 the basal segments combined. 



Thorax : Lateral bristles of the mesonotum developed ; dorso- 

 central bristles rarely absent before the suture. Scutellum 

 with a pair of long, marginal bristles and sometimes with pile 

 between them. Postscutellar region bare. Mesopleuron almost 

 always with long pile. 



Legs : The legs are generally slender but very robust in 

 Lastauroides crassitarsis. Claws sharp; pulvilli developed. 



Wings : The first basal cell a little larger than the second, 

 and sometimes of the same length. 



Abdomen : The first four segments in males with long pile, 

 sometimes abundant; in females the pile always well reduced. 

 Genitalia of male conspicuous, with a rotation of approximately 

 90 degrees. 



The following characters distinguish this genus from others 

 of the Lastaurus Loew complex : The disposition of the second 

 palpal segment to arise at an angle ; the form of the face 

 which is plane at the top and salient at the buccal border ; 

 the fusiform third antennal segment which is rarely longer 

 than the basal two combined. Length 13 to 17 mm. 



Distribution : Neotropical : Lastauroides alexanderi 

 Carrera (1949) ; albomarglnatus Carrera (1949) ; cras- 

 sitarsis Macquart (1838) [=atratus Bigot (1878) ] ; hir- 

 tuosus Wiedemann (1821) ; melaleucus Schiner (1868) ; 

 mixtus Carrera (1949) ; modestus Carrera (1949) ; 

 niger Carrera (1949). 



Chylophaga, new genus 



Figures 135, 546, 1073, 1082, 1712, 1731, 1966, 2017 



Type of genus: Deromyia australis Ricardo, 1912. 



Elongate, rather stout flies with comparatively slen- 

 der, cylindrical abdomen. On the face the bristles are 

 restricted to the epistoma. They appear to resemble 

 Diogmites Loew in most details but are at once sep- 

 arated by the non-rotate male terminalia. This condi- 

 tion might possibly ally them to the non-rotate 

 Stenopogon Loew group, but because of the tibial spine 

 it is much more likely that they are related to Saropo- 

 gon Loew. The strong, dorsocentral bristles, together 

 with the soft, dense, fine, erect pubescence of the an- 

 terior tarsal segments separate them from most genera 

 with which they might be confused. Length 20 mm. 



Head, lateral aspect : The head is of normal length ; 

 the face very slightly visible above in profile but more 

 prominent below. Anterior profile oval, slightly flat- 

 tened in the middle. The occiput is narrowly visible in 

 the middle, slightly more prominent below, obliterated 



near the vertex ; pile of occiput restricted to the extreme 

 lower portion where there is a tuft of not very long, 

 fine hairs. There is a narrow, double row of slender, 

 weak bristles beginning near the bottom of the occiput 

 and continuing to the vertex; the upper elements are 

 scarcely thicker, except perhaps behind the ocellar pro- 

 tuberance ; these bristles are set well back from the eye 

 margin. The proboscis is rather slender, of moderate 

 length, directed obliquely downward, nearly cylindrical, 

 but with a strong, dorsomedial, thinned ridge. The base 

 is unswollen, the apex tapered to a blunt point but en- 

 tirely confined to the dorsal portion for the ventral 

 margin is plane. Apex with fine pile, the ventral por- 

 tion on the basal half with a number of long, stiff hairs. 

 Palpus clearly of two segments; first segment exca- 

 vated, second segment without pore, and slightly angu- 

 late in attachment. The palpal pile is fine and long and 

 situated on the ventral and lateral surfaces and there 

 are some 3 ventral bristles, 2 dorsal and 3 apical bristles. 



The antenna attached at the upper third of the head ; 

 it is rather long and slender, the first segment is two- 

 thirds as long as the second, the third segment is longer 

 than the other segments together. This segment is at- 

 tenuate basally and apically and therefore somewhat 

 swollen in the middle. The apex of the third segment 

 bears an extremely short, subsegment which medially is 

 obliquely truncate, open and bears centrally a minute, 

 short, distinct spine. First and second segments with 

 appressed, stiff setae dorsally, as many as 14 on the 

 second segment. These segments ventrally bear long, 

 oblique, stiff, sharp bristles more numerous on the first 

 segment which may have 17 elements including lateral 

 bristles. The third segment bears 5 dorsal setae. 



Head, anterior aspect : The face below antenna is little 

 more than a fifth the head width and divergent below. 

 The face cover consists of micropubescence ; pile is ab- 

 sent; bristles are confined to an epistomal row of 6 

 pairs of long, quite stout, pale, obliquely directed 

 bristles and 2 pairs immediately above the epistomal 

 row. Subepistomal area large, excavated, oblique and 

 shallowly concave and pubescent laterally. The front 

 is slightly divergent near the vertex and bears micro- 

 pubescence only. The vertex is moderately excavated, 

 the ocellar protuberance high with nearly vertical sides, 

 the ocelli of moderate size; the protuberance bears 3 

 or 4 pairs of long, very stout, divergent bristles ; the eye 

 facets are strongly enlarged centrally and zoned off 

 from the remainder by an impressed dorsal line. Eyes 

 brilliantly green to purple. 



Thorax : The mesonotum and the pleuron pollinose. 

 Mesonotal pile scanty but fine, setate and suberect, and 

 confined to the anterior submedial region extending as 

 a band behind the humerus. There is a single row of 

 fine, rather stiff, subappressed, backwardly directed, 

 comparatively long acrostical elements, confined to the 

 anterior half, a wide bare stripe on either side. There 

 is a single row of 5 long, stout, dorsocentral bristles be- 

 fore the suture and still longer and stronger elements 

 continued nearly back to the scutellum. Humerus an- 

 teriorly with 4 weak bristles and some scattered setae. 



