INSECTS OF NEW BRUNSWICK. 21 



part preserved, is a little nearer to the vein above, and to its first branch, than to the vein 

 below, and may possibly, not improbably, be a branch of the first vein mentioned, parting 

 from it further toward the base than the fracture of the specimen allows us to see ; 

 the two veins below it seem to belong together ; the bit of margin preserved, covering 

 only two interspaces, is slightly convex. The cross veins are weak, but tolerably uniform, 

 and either direct or slightly oblique, or occasionally a little irregular ; they are nearly 

 equidistant as a general rule, but more frequent in the outer of the two interspaces touch- 

 ing the margin than elsewhere. The length of the fragment is 15 mm. 



The fragment then consists of some curved veins striking the lower margin of a wing, 

 one at least of which is one of two or more inferior and, so far as can be seen, simple 

 branches of a principal longitudinal vein, whose course would make it terminate either at 

 the very tip of the wing, or, if it afterwards curved considerably, very near the extremity 

 of the lower margin. This principal vein probably belongs either to the scapiilar or exter- 

 nomedian, while the lower curved veins appear like branches of the interuomedian vein. 

 The wing cannot therefore be referred to the vicinity of either Platephemera or Gei-eph- 

 emera, both on account of the relations to each other of the veins, and of the nature of 

 the reticulation, the latter being certainly polygonal in this region in both these genera ; 

 while the irregular course of the veins themselves in Platephemera and their considerable 

 ajjical divarication in Gerephemera constitute peculiarities not observed in the simple frag- 

 ment under discussion. So far as the course of the veins is concerned it can be much 

 better, and indeed very well, compared to Dictyoneura and its allies ; but in all these 

 insects the interspaces are filled with a minute polj^gonal reticulation (wherever it is 

 preserved), which is such a characteristic feature that Dyscritus can by no possibilitj' be 

 considered as very closely allied to them. 



The neuration is altogether diflFerent in Xenoneura, finding nothing at all comparable 

 in this region. The longitudinality of the veins throughout Lithentomum seems to forbid 

 any close comparison with it. But in Homothetus we do find some points in common 

 with Dyscritus ; for while the reticulation is much more sparse in the former, there is a 

 certain regularity about it similar to what we have in the latter, while the curving of the 

 interuomedian veins and their parallelism certainly resemble in a general way the same 

 features in Dyscritus. And if we presume the fragment of Dyscritus to be broken from 

 near the middle of the wing, we may see a not distant resemblance between the longitudinal 

 vein of Dyscritus aud its two visibly connected branches, and the main branch of the scap- 

 ular vein in Homothetus ; while the upper, independent, curved vein of Dyscritus may be 

 taken perhaps for the externomedian vein, and the other two nervules for branches of the 

 interuomedian vein. The resemblance is at least sufficient to make us believe we have 

 here a clue to its relationship ; while at the same time it differs so much from it that we 

 cannot associate the two even generically ; for if they are to be compared in this way at all, 

 the lower stem of the main scapular branch, as seen in Homothetus, must either have 

 become single and simple in Dyscritus, or it must have assumed the longitudinality and 

 mode of bifurcation of the upper stem. 



There is nothing, however, in the fragment to show what the connection of the main 

 scapidar branch may have been, and consequently nothing to prevent the reference of 

 this wing to the Sialina, where the relations of the veins would be the same. Judging 



