TACHYDROMIA. 139 



capite brevior. Palpi oblougi, proboscidis longitudine. Antennae 

 4-articvilat£e, parvfe; articulus primus brevissimus iucouspicuus, 

 tertius compressus, ellipticus ; quartus longus, setifonnis. Alarum 

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

 analis null(B. Pedes cursorii ; coxa femoribus breviores ; femora 

 antica crassa. 

 Mas. Anus obtusus. 

 Fceni. Anus acutus. 



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

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

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

 Proboscis perpendicular, shorter than the head. Labrum acute. 

 Lingua setiforra. 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. 

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

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

 joint verv 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. AVings 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 ; coxce 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. 

 Fem. Tip of the abdomen acute. 



The Tachydromice run with great swiftness, aud appear from 

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

 leaves of shrubs, and about the shores of lakes aud the bauks 

 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, w^ould belong to Platypalpus. They do not perfectly 

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

 formation of a new one, to wliich Meigen's name Tacliypeza 

 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, nlis albis fiisco-bifasciatis, venis secnnda, ter- 

 tiaque approximatis, halteribus flavis, coxis femoribus anterioribus basi 

 subtusque genubusque fidvis, tarsis Jlavis apice nigris. Long, j- 1 ; 

 alar, li-2 liu. 



