210 Mr. W. E. Shuckard's Description of the 



more than half the length of the post-costal, or about one third of the 

 entire length of the wing, and then leads off at an obtuse angle to 

 join the post-costal just before its junction with the stigma. The 

 anal is the fourth longitudinal nervure, which also extends from the 

 base to the sinus at the apical extremity of its posterior margin : a 

 transverse nervure unites the externo-medial and anal, and which I 

 propose calling the traiisver so-medial. These nervures, which I con- 

 sider the primary nervures of the wing, severally inclose what have 

 hitherto been called collectively the basal or humeral cells, but to 

 which I purpose applying different names (derived from the nervures 

 which inclose them), that they may be the more readily distinguished 

 from each other. The first, or that very narrow one between the 

 costal and post-costal ner\'ures, is the costal cell ; the second is that 

 placed between the post-costal and externo-medial nervures and 

 M'hich I call the externo-medial cell : that inclosed between the ex- 

 terno-medial and anal nervures parallelly, and terminated at its apex 

 by the transverso-medial, is the interno-medial cell ; and the cell 

 seated between the anal nervure and the posterior margin of the 

 wing is the anal cell. 



From the interior margin of the stigma arises the radial nervure> 

 which makes a curve and then joins the costal upon the margin of 

 the wing : the lanceolate space thus inclosed forms what is called 

 the radial or marginal cell. The cubital nervure is nearly parallel 

 with the radial, and originates from the externo-medial near its junc- 

 tion with tlie post-costal ; this extends to the apical margin of the 

 wing just below its extreme apex. The space thus inclosed is divided 

 bv three transverse nervures, which I propose calling the transverso- 

 cuhitals, inclosing as many spaces forming so many cubital or sub- 

 marginal cells, a fourth being formed in consequence of the cubital 

 nervure extending to and joining the apical margin. The third 

 nervure, originating from the primary nervures of the wing, is what I 

 call the discoidal ner\iire, — (it is from this that I anticipate the chief 

 results), — and which, commencing at the transverso-medial, extends 

 in a direct line to the disc of the wing directly between the stigma 

 and the sinus, when it makes a sudden curve at a right angle back- 

 wards and joins the anal nervure close to the sinus. From this dis- 

 coidal nervure at the centre of its apical return another springs, 

 forming what I call the subdiscoidal nervure, and which here ex- 

 tends to the posterior margin of the wing. From the cubital nervure 

 two others originate ; these are called the recurrent nervures, the 

 first of which always inosculates at the angle of the discoidal 

 nervure, and the second just beyond the centre of the subdiscoidal. 

 By the reticulation of these four nervures several cells are formed 



