TACHYDROMIA. 139 



capite brevior. Palpi oblongi, proboscidis longitudine. Antennae 

 4-articulatae, parvae ; articulus primus brevissinius incoiispicims, 

 tertius compressus, ellipticus ; quartus longus, setiformis. Alarum 

 vena cubitalis simplex ; vence externo-mediae 2 ; areola discoidalis et 

 analis nullcc. Pedes cursorii ; coxa femoribus breviores ; femora 

 antica crassa. 

 Mas. Anus obtusus. 

 Fcem. Anus acutus. 



Body black, minute, long, slender, smooth, shining ; dull in the last 

 two species. Head oval, narrower than the thorax. Eyes aeneous or 

 green, slightly parted above, connected beneath. Ocelli 3, in front. 

 Proboscis perpendicular, shorter than the head. Labrum acute. 

 Lingua setiform. Maxillae setaceous, as long as the lingua. Palpi 

 generally as long as the proboscis, oblong, large, drooping, bristly at the 

 tips, fringed on the outer border with short hairs. Labium cylindrical. 

 Antennae 4-jointed, porrect, inserted in the middle of the face, ap- 

 proximate at the base, diverging upwards, as long as the head; first 

 joint very short, inconspicuous; second short, cylindrical, somewhat 

 bristly ; third rather long, elliptical, compressed, hairy beneath ; last 

 long, setiform. Thorax long-oval ; scutellum semicircular, rather nar- 

 row. Wings pubescent, obtuse, incumbent, longer than the body ; 

 cubital vein simple ; externo-medial veins 2 , discal areolet and anal vein 

 none. Halteres uncovered. Abdomen cylindrical, rather long. Legs 

 slender ; coxae shorter than the femora ; fore femora incrassated, with 

 a double row of minute spines beneath ; fore tibiae clavate, with a 

 series of spines on the inside ; tarsi longer than the tibiae ; meta- 

 tarsus as long as all the other joints ; ungues and onychia distinct. 

 Male. Tip of the abdomen obtuse. 

 Fern. Tip of the abdomen acute. 



The Tackydromia run with great swiftness, and appear from 

 the spring to the autumn, on trunks of trees, palings, stones, 

 leaves of shrubs, and about the shores of lakes and the banks 

 of rivers. The species may be thus distributed : 



a. Palpi as long as proboscis. Species 1-4. 



a a. Palpi shorter than proboscis ; a trace of subanal vein. Sp. 5, 6. 



"The last two, according to the synoptic table of the 

 genera, would belong to Platy palpus. They do not perfectly 

 agree with either of the two genera, and perhaps require the 

 formation of a new one, to which Meigen's name TacJiypeza 

 might be applied restrictedly." A. H. H. 



1. arrogans, L. fn. 1857 (1761) ; Fb. ; Gm. ; Fin. ; LI. ; Mg. ; 

 Mq. ; Ztt. ; Ct. ! b. e. 477. Nigra, antennis basi fulvis, thorace ni- 

 gro-aeneo vel nigro-viridi, alls albis fusco-bifasciatis, venis secunda ter- 

 tiaque approximates, halteribus flavis, coxis femoribus anterioribus basi 

 subtusque genubusque fulvis, tarsis flavis apice nigris. Long, f-1 ; 

 alar. H-2 lin. 



