in the Tetrameruiis and Trimerons Coleopfera. 71 



liis " Coccinelle à 15 points noirs," although he considered the 

 genus as triraerous*. And the fact is, that this truly tetra- 

 merous structure prevails, as far as I have observed, throughout 

 all the insects hitherto called trimerous : for instance, in Eumor- 

 plnis immarginatus, a Sumatran insect, which I more particularly 

 specify, for the same reason as the Javanese Coccinello, because 

 they are both large species in a group of which the insects are 

 generally small, and because the tetramerous structure of their 

 tarsus is therefore visible to the naked eye. 



These very remarkable facts destroy even the very nomencla- 

 ture of M. Latreille's system, and throw doubt on the description 

 of almost every genus that is not recorded as pentamerous in 

 the Genera Insect or urn. In this stage of the investigation, there- 

 fore, two important questions arise, which require much more 

 development than I am able to give them in the present crude 

 sketch. These are, first. What coleopterous genera possess only 

 four joints to each of their tarsi ? and, secondly, Considering such 

 tetramerous tarsi as typically pentamerous, what articulation is it 

 that is evanescent in these genera ? Such are questions intimately 

 connected with the doctrine of natural affinities, as it relates to 

 Coleopfera ; and I therefore beg leave to conclude this paper 

 with a few remarks, which may be interesting to those who may 

 be inclined to take up the subject. 



Heteromerous insects are, as before said, so called by MM. Du- 

 meril and Latreille because they have five articulations to each of 

 the four first tarsi, and only four to each of the two last. This, as 



* In his lirst letter to the editors of the Philosophical Magazine, Mr. Kirby states, 

 on the authority of Mr. Spence, that Millier had discovered the third joint in the tarsus 

 of Cocciitella ; but as Mr. Kirby has not been able to refer me to the work in which 

 Miiller published this discovery respecting the Tritnent of the French system, I can 

 only mention the fact, contenting myself, in consequence, with having been the first to 

 make known to the public the true construction of the tarsus in Uie insects called 

 Tet ramera by the French entomologists. — Ma^ IS'25. 



far 



