384 INSECTS. DIPTERA. 



1. First joint of the antennae longest. 



Gen. TOXOPHORA, XESTOMYZA. 



2. First joint of the antennae the length of the last and often shorter. 



Gen. APATOMYZA, THLIPSOMYZA, AMYCTES, GERON, PHTHIRIA, CYL- 



LENIA, (rostrum short.) 



II. Abdomen short, triangular. 



Gen. PLOAS, BOMBYLIUS, USIA, LASIA. 



Gen. BOMBYLIUS, Lin. Asilus, Geoff. 



Rostrum longer than the head ; antennae of three joints, the 

 third the longest, slender towards the end and terminated 

 in a small style, the second shortest ; body broad, hairy, with 

 the head rounded and almost occupied by the eyes ; three 

 small ocelli placed in a triangular form on the summit ; wings 

 large, horizontal ; abdomen flattened, triangular and broad ; 

 feet long and slender. 



The insects of this genus are very agile, and fly with much rapidity. They hover 

 over flowers without alighting, and introduce their long rostrum to suck the honey. 

 In flying they make a humming noise. 



B. major, Lat. Body short, covered with yellowish gray hairs ; 

 rostrum black, pointed, as long as the body ; wings long, whitish, 

 transparent at the anterior margin and extremity, brown from 

 the base to near the extremity of the exterior border, forming a 

 large waved spot on the middle of the wing ; feet long, gray, 

 with blackish spines ; tarsi black. 6 lines long. Inhabits Eu- 

 rope. Shaw, vi. pi. 113. 



B. medius, Lin. Body covered with long reddish hairs ; antennae, 

 rostrum, and feet black ; legs covered with spines of the same 

 colour ; wings half brown and half white, with small obscure spots. 

 Inhabits Europe. Sharv, vi. pi. 113. 



TRIBE XL VESICULOSA, Lat. 



Head inclined and the thorax elevated ; balancers covered by a 

 plate ; abdomen inflated and vesicular ; antennae sometimes 

 very small, of two joints, with a terminal seta, or of three 

 joints, of which the last, destitute of style or seta, is elon- 

 gated or cylindrical, or tumid and in the form of a button. 



I. With a rostrum. 



Gen. PANOPS, CYRTUS. 



II. Without a rostrum. 



Gen. ASTOMELLA, ACROCERA, O&EODES. 



Gen. PANOPS, Lam. 



Rostrum elongated and cylindrical, extended horizontally un- 

 der the body, with two projecting palpi, filiform and biarticu- 

 lated, at the base ; antennae of three joints, cylindrical, pro- 

 jecting, a little longer than the head, the two first joints short, 

 the last long, and without apparent division. 



