SYSTROPIN.E 



513 



SYSTROPINiE. 



Very elongate, thin, bare, long-legged species. Basal joint of the 

 antennae very long, thin, and almost bare. Occiput hollowed out. 

 Posterior cells three only. 



Head (fig. .302) transverse, when seen from above more than twice as broad as 

 long ; face and frons quite bare ; mouth-oi^ening long and 

 narrow, being extended almost up to the antennae. Below 

 the touching eyes the small frons and the narrow face 

 gradually widen down to the lowest level of the eyes, 

 the face at its middle being only about one-eighth the 

 width of the head and widening to about one-sixth at the 

 lowest part ; back of the head excavated and bare ; ocelli 

 three, placed on a small but distinct tubercle. Collar small 

 and short. Proboscis long, thin, and porrect, as long as or 

 twice as long as the thorax ; palpi small. Eyes in both 

 sexes bare and touching on the frons (narrowly separated 

 in the female of S. chilensis and of Dolichomyia), and 

 without any indentation at the middle of the back margin ; 

 facets in the male rather larger above and in front than 

 in the female. Antennae very elongate, thin, and porrect, 

 as long as the head and thorax together (but in *S'. chilensis 

 only about as long as the head), very closely approximated 

 at the base and scarcely diverging up to the end of the 



long thin basal joint ; basal joint nearly or quite half the pio. ZQ-i.—Systropus fmnoides. 

 length of the antennae and with some minute bristles x 9. 



beneath ; second joint about a third the length of the first, 



and diverging ; third joint still more diverging, elongate but slightly widened, 

 flattened, and usually pointed. 



Thorax humjied anteriorly though not conspicuously so, bare of all bristles and 

 with very slight short pubescence, but with a large prgealar depression on each side ; 

 prothorax moderate in size and without bristles ; hypopleurse and metapleurse large 

 or very large, and bearing slight down but no bristles. Scutellum rather small, 

 sloping down from the thorax to the abdomen and concealing the middle part of 

 the metanotum, but the latter has a peculiar always pale colored membranous tubercle 

 on each side. 



Abdomen very long, thin (like Leptogaster), and quite bare, with nine segments in 

 the male, but only eight in the female. Genitalia ( = last segment) of the male 

 usually moderate in size though distinct and sometimes knobbed, of the female 

 sharply compressed and ending on the underside in two small points. 



Legs rather short and thin on the anterior pairs, but the hind pair very long 

 and rather thickened, bare of bristles and pubescence except for three rows of 

 spicules and some short spurs on the hind tibiae and some plantar spines on the 

 tarsi, and in some species an antero-ventral spine occurs near the middle of the 

 hind femora. 



Wings (fig. 303) comparatively short, being much shorter than the elongate 



Pio. S03.—Systropus fcenoides. x 7. 



abdomen ; mediastinal and subcostal veins very long ; prsefurca very short ; radial 

 vein only moderately curved up to the costa and ending nearer to the subcostal 

 than to the upper branch of the cubital fork ; submarginal cells two, rarely 



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