l".)i) AniKils E)itoniulo^ical Society oj America [\'ol. III. 



is a deep trough-like dejjression. whose ends are elosed by a con- 

 tinuation backward onto the scutellum of the ridges, spoken 

 of previously, which may be designated as the dorso-lateral 

 ridges. On the mesonotum, just in front of the trough and 

 branching off from the dorso-lateral ridge is a short oblique ridge 

 which extends outward and forward to the insertion of the fore- 

 wing. The sides of the trapezoid are continuations backward 

 of the dorsal-lateral ridges. Near the rear margin of the scu- 

 tellum these become lost. Along this margin there is a reflexed 

 edge or flange which extends obliquely towards the insertion 

 of the fore-wings. 



The surface of the lateral portions of the scutellum lies at 

 a sharp angle with that of the median portion (trapezoidal) 

 and extends from the dorsal lateral ridge downward and for- 

 ward to the base of the forewing. As already stated the hinder 

 margin of this portion is reflexed nearly to the wing attachment. 

 The mesothoracic plcuron is a large plate which lies below the 

 wings, its posterior margin being approximately indicated by 

 an oblique groove extending downward and backward from 

 beneath the fore-wing to just beneath the hind wing where it 

 bends a little more downward, and takes a nearly straight path 

 to the meso-coxa. From here it passes forward, curving some- 

 what until about opposite the base of the fore coxa. It then 

 turns sharply upward, and passing by the base of the fore-coxa 

 follows along the edge of the prothorax to the base of the fore- 

 wing. 



There are several ridges and grooves on this plate, but noth- 

 ing which can be termed a distinct suture, that is, dividing the 

 l^leuron into subordinate plates. The meso-coxa is attached 

 near the extreme posterior edge of this plate, occupying about 

 one-third of its width, which is somewhat greater ventrally 

 than dorsally. 



METATIIOUAX. 



Just to the rear of the scutellum and below it is a narrow 

 plate which extends from one hind wing to the other and is 

 known as the jjost scutellum. The rear margin of this plate 

 is reflexed as in the case of the rear margin of the scutellum, 

 and extends forward nearly to the base of the hind wings. 



The ])art of the metapleuron nearest the hind wing (epi- 

 sternum) is triangular in outline. The apex of the triangle 

 extends ventrally and comes to a point just between the meso- 



