THE ENTOMOLOGIST. 25 



difference in the length of the antennae, and the incrassation 

 towards the tip is rather less abrupt. The wings are rather 

 less diaphanous than in Nubigena, decidedly more so than in 

 Trifolii; their colour has a tinge of opaque green, which is all 

 but invisible in Nubigena, and there is none of that metallic 

 green which adorns Trifolii: this observation applies only to 

 the variety, and not to the type specimens of Exulans, some 

 of which are richly adorned with gold-green, especially the 

 females ; the red spots are five in number, and disposed 

 much as in Trifolii ; I find no trace of the sixth spot, which 

 is always indicated in Nubigena, however fused and united 

 with other spots ; all the red markings are duller than either 

 in Trifolii or Nubigena, and the tint of the red is more of a 

 dull carmine; the basal subcostal spot is long and pointed, 

 far surpassing the second basal spot, which is clearly defined, 

 and never appears united with any other red spot ; in this 

 respect it agrees with Trifolii ; the three remaining red spots 

 are distinct and well-defined ; the black hind border of the 

 hind wings is accompanied by a smoky cloud, narrower in 

 the female, broader in the male ; the wing-rays are partially 

 of the same dull smoke-colour; the body is black and hairy. 

 The character essentialis, or nomen-specificum, given as 

 diagnostic of the species Alarum anterioriim coslis s/tbsul- 

 phttreis, is not apparent in Scotch specimens. Typical 

 specimens of Exulans from the Swiss Alps possess this and 

 other characteristics, which I have purposely omitted to 

 notice. — Edward Newman. 



Notes on Aphides. — The study of geographical distribution 

 of insects is inductive to enquiry as to the mode by which 

 this arrangement has been effected. Passing over earlier 

 cosmical changes, investigation may begin with the glacial 

 period, which was preparatory to the present aspects of 

 nature. During the prevalence of this epoch insect life was 

 mostly limited to the regions about the middle zone of the 

 earth, and from thence the assemblage of insects spread and 

 converged to the north and to the south, and these middle 

 districts might have been more extensive than they are now, 

 as there are indications and traces of large continents that 

 formerly occupied parts of the Atlantic, and of the Pacific 

 and of the Indian Ocean. During the continual diminution 



