OF THE ANNULOSA. 577 



determine whether these insects come nearest to the He- 

 mipterous or Homopterous type ; but I may observe that 

 probabiUty is on the side of the latter supposition, since 

 the genus Ranatra bears a strong analogy to the Ephe- 

 mera. We perceive, however, the wings of the Hydro- 

 coriscs becoming gradually more coriaceous, or rather 

 corneous, and opaque; we perceive them crossing one 

 another more and more, in order to ma"ke room for the en- 

 largement of the scutellum, which, with the two ocelli 

 and quadri-articulate rostrum, is the typical character of 

 the true Hemiptera. 



On account of the similarity in the structure of their 

 mouths, but particularly in consequence of the sheath of 

 the rostrum in both orders being articulated, Fabricius, 

 Lamarck and Latreille have all admitted the proximity of 

 the Suctoria of Degeer to the Ilsmiptera. " En divisant," 

 says Latreille, " comme V a fait M. de Lamarck, les insectes 

 qui subissent des metamorphoses en deux grandes coupes, 

 ceux qui out des mandihules et des machoires, et ceux oH ces 

 organes sont transformes en un sucoir, I'ordre de Sitceurs 

 semble el re entremediaire entre les Hemipteres et les Di- 

 pthxs." Yet, notwithstanding the justice of this remark, 

 notwithstanding that M. Latreille mentions this affinity of 

 the common flea to the Hemiptera in all his works, it is 

 very singular that in his arrangement he never acts wholly 

 upon its truth, and in the Regtie Animal even totally dis- 

 regards it. This inconsistency without doubt arises from 

 his not having been able to make his observation accord 

 with his system ; and unfortunately, rather than disturb 

 this, he is often apt to overlook the advantages to be de- 

 rived from his discovery of an affinity. Nothing, however, 

 stamps such a value on his works as tlie candour with 



