STRUCTURES USED IN CLASSIFICATION. 



15 



Coupled with these extreme anteunal developments we find ex- 

 ternally toothed or mucronate tibiae, and despite the practical 

 absence of a beak, we have no hesitation in placing the Scolytidae 

 as the highest of the Ehynchophora. 



Leaving the antennae, we shall now mention a few structures 



that prove useful in classification 

 though subordinate to those al- 

 ready described. The legs afford 

 many such. The coxae may be sep- 

 arated or contiguous. The tro- 

 chanters are usually short and in- 

 conspicuous, but are long in Apion- 

 inse, as already shown in Fig. 14. 

 The femora are often toothed and in 

 Orchestes are remarkably enlarged, 

 The tibiae are equally subject to variations and are, through- 

 out the Scolytidse, with few exceptions, externally 

 serrate or toothed. The apex of the tibia 1 is the 

 scat of many characters of service. The truncate 

 oval tip common in Otiorhynchiuae, Hylobiini, etc., is 

 sometimes called the corbel, especially when the in- 

 sertion of the tarsus is on the inner side a little above 



Fig. 18. B, Femur of Orchcstcs; C, 

 tibia of BarynotiiA showing the closed 

 corbel, surrounded by a row of hairs. 

 (After Kuhnt.) 



Tibia 



the ti]. This is said to be "open" when its edge is 



Fig. 19. 



interrupted on the inner side by the articular cavity of 

 of the tarsus, and "closed 1 ' when the cavity does not reach it and 

 the oval margin is entire. (Fig. 18, C.) In other species the 

 tibire may end either in a stout blunt hook or spur, or in a spine. 

 In the latter case they are said to be mucronate. (Fig. 37, p s.) 

 The tarsi also present man}' modifications. In the arboreal 

 Ourculionida 1 the third joint is commonly dilated 

 (Fig. 20), bilobed and spongy pubescent beneath, 

 but in the palustral and epigeal species this form 

 is seldom seen, the tarsi being equally narrow. In 

 the relative proportions of the joints there is also 

 much variation, and the subfamily Platypodinae is 

 distinguished by the great elongation of the first 

 tarsal joint. The claws of the tarsi, though natur- 

 Show- a ^ v small < a l so furnish useful characters. They 

 bilobed third are lisu allv two in number and may be simple, 



tarsal joints. 



(After Kuhnt.) connate, toothed, appendiculate or cleft.* 



'For a definition of these terms see Coleoptera of Indiana, p. iS; also Fig. 37, /; I. 



