420 



COLEOPTERA. 



COLEOPTERA. 



In the highest suborder of this series, the Coleoptera, we 

 find the most complete metamorphosis and the greatest speci- 

 alization of parts, with 

 a more complete con- 

 centration of them to- 

 wards the head than in 

 the lower suborders. 

 They are at once rec- 

 ognized by the elytra, 

 or thickened horny fore 

 wings, which are not 

 actively used in flight 

 (the hind wings being 

 especially adapted for 

 that purpose), while 

 they cover and encase 

 ^ the two posterior seg- 

 ments of the thorax 

 and the abdomen. The 

 l^ro thoracic ring is 

 greatly enlarged, often 

 excavated in front to re- 

 ceive the head. These 

 characters are very per- 

 sistent ; there are few 

 aberrant forms and the 

 suborder is remarkably 

 homogeneous and easily 

 limited. 



The head is free from 



Fig. 345. the thorax, but less so 



than in the preceding suborders ; it is scarcely narrowed behind, 



and its position is usually horizontal. The eyes are usually 



Fig. 345, under surface of Harpalus raliginosus. (After Leconte.) a, ligula; 

 b, paraglossas ; c, supports of labial palpi ; d, labial palpus ; e, mentum ; /, inner 

 lobe of maxilla; g, outer lobe of maxilla; h, maxillary palpus; i, mandible; k, 



