228 [April 



The thorax is rather long, and remarkable for the great and unusual 

 development of the rnesosternum, in consequence of which the fore 

 coxae are at a considerable distance from the intermediate ones ; the 

 collare is entirely concealed under a projecting gibbosity of the meso- 

 notum ; on the underside, the prothorax is extended into a long, nar- 

 row, cylindrical neck, to which the head is fastened ; the metanotum is 

 also much developed, rather long and horizontal. 



The feet are long and slender; their pubescence hardly perceptible; 

 the last joint of the tarsi of the male shows on the underside, at the 

 basis, the excision characterizing the male sex in many genera. The 

 tibiae have no spurs at the tip. and the empodia are imperceptible. 



The wings are rather short for the size of the body, and not broad. 



The first longitudinal vein joins the costal very early and very soon 

 beyond the origin of the second longitudinal vein; the mode of this 

 junction of the first vein with the costa is also peculiar; instead of 

 running parallel to the costa and then taking a sudden turn towards it. 

 fas in must Limnobina), the first vein gradually converges towards the 

 costa and finally coalesces with it, so that, beyond their junction, the 

 costa becomes much stouter. The auxiliary vein is very closely approxi- 

 mated to the first longitudinal and ends in the costa almost opposite 

 the origin of the second vein ; the auxiliary cross-vein is not far from 

 its tip ; there is no vestige of a stigmatical cross-vein. Then 1 is no 

 mhmarginal celt, as the second longitudinal vein does not emit any 

 nth /• vein ; the first posterior cell follows immediately after the margi- 

 nal cell. The more correct view of this neuration would perhaps be to 

 consider the section of the second vein, lying beyond the small cross- 

 vein, as the third vein, thus assuming that the exterior section of the 

 second vein, and not the third vein is obliterated. However, for brevi- 

 ty's sake, I have called the whole vein, second longitudinal vein. The 

 fourth vein starts, as usual, from the fifth, very near the basis of the 

 wing, being slightly arcuated at its origin, and connected at this place 

 with the first vein by a small, but very distinct, cross-vein. A thicken- 

 ing of the alar membrane almost always exists at this place in the Lim- 

 nobina; sometimes it assumes the appearance of a vein ; in the present 

 case, however, this cross-veiu is particularly distinct, because the origin 

 of the fourth vein is a little more distant than usual from the basis of the 

 wing. Of the two branches of the fourth vein, the posterior one is 

 forked, and a cross-vein between this fork and the anterior branch 

 closes the discal cell. 



The sixth vein is very closely approximated to the fifth for more 

 than one-third of its course, and then suddenly diverges at an acute 



