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•HE American Journal of Science and Arts, Vol. XLIV, July, 1867.1 ( 



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ON THE 



SYSTEMATIC VALUE OF RHYNCHOPHOROUS COLEOPTERA. 



An Abstract of a Memoir read before the National Academy of Sciences, at 

 Washington, Jan. 24th, ISe?. 



By JOHN L. LeCONTE. 



In the empirical arrangement of the families of Coleoptera, 

 which has resulted from the adoption of the tarsal system of 

 division, the families contained in the great natural group of He- 

 teromera are followed by the Curculionidse and Scoly tidse, which 

 more or less subdivided into smaller families, have been sup- 

 posed to establish a linear relation between the rostrated Hete- 

 romera (Salpingus, Rhinosimus, &c.) to the Cerambycidse and 

 Chrysomelidge, the great types of the Pseudotetramera, or Sub- 

 pentamera, of various authors. 



It is the object of the present investigation to determine the 

 limits, and the relations of the first mentioned of these types, 

 the Rhynchophora. 



The inferiority of this type is manifested, not only in the lar- 

 val condition by the limited number or absence of visual lenses, 

 the want of locomotive appendages, the feeble development or 

 entire want of antennae, and the unchitinized epidermis; but 

 also by the combination in the imago of characters belonging to 

 a perfectly developed organism with others pertaining to an infe- 

 rior grade in the scale of Coleoptera. 



Thus, for instance, while we perceive in the other series of 

 beetles, that the lower forms retain certain larval characters, as 

 evidenced by the extension of the coxae, the imperfection of the 

 anterior coxal cavities, the softness of the integuments, and the 

 want of centralization in the abdomen, all such degradational 

 characters are absent in the Rhynchophora. 



Other characters representing low grades in their respective 

 series do not appear in the Rhynchophora, such as vegetative 

 growth of the organs of sense, indicated by pectinate or flabel- 

 late antennae, or excessive length of palpi. 



On the contrary, we find in the Rhynchophora, that the in- 

 teguments are perfectly chitinized : the elytra never abbreviated 

 or wanting ; the anterior coxae are always completely enclosed ; 

 the ventral segments, usually five, never exceed six in number. 



The plan of degradation, in passing from the higher to the 

 lower forms, is by the extension of the longitudinal axis of the 

 body, in its anterior half; this is usually most strongly manifes- 

 ted in the head, and exhibited not only by the length of the 

 beak, but by the conformation of the lower floor of the mouth. 



