INSECT A. 



863 



Fig. 339. 



form, are never terminated by a pectinated club. 

 It includes many genera of dissimilar habits, 

 the darkling-beetles, Blapsida, the meal-bee- 

 tles, Tenebrionida, and the Cantharida, the 

 oil-beetles and blister-flies. 



In the sixth section, Brachelytra, (fig- 341 ), 



fig. 341. 



Timarcha tenebricosa. 



other. It is an insect of this tribe, Hallica 

 nemorum, that often occasions so much injury 

 to the agriculturist by destroying his crops of 

 turnips immediately after the young plant ap- 

 pears above ground. The perfect beetle, 

 scarcely larger than a millet-seed, deposits its 

 eggs upon the under surface of the first leaves, 

 and the larva when hatched penetrates into the 

 substance of the parenchymatous tissue, be- 

 tween the cuticle of the upper and under sur- 

 face of the leaf, where it lives until it is ready 

 to undergo its transformations in the ground.* 

 In some years the plants are attacked by such 

 prodigious numbers of these insects that many 

 thousand of acres are destroyed in a few days. 

 The loss sustained by the devastations of this 

 insect in Devonshire in 1786, is said to have 

 been not less than 100,000 f 



In the fourth section, Pseudo-trimera, WEST. 

 the insects have only three distinct joints in 

 their tarsi, although a fourth one, exceedingly 

 minute, and which like the additional one in 

 theTetramera was first noticed by Messrs. Kirby 

 and Spence,t exists at the articulation of the last 

 joint, as in the insects of the third section. The 

 Pseudo-trimera are distinguished by their tarsi, 

 by their oval or hemispheric shape, and by the 

 antennae ending in a three-jointed club. The 

 larvae are hexapodous and active ; those of the 

 common lady-cow, Coccinella, feed upon 

 aphides, and other genera upon fungi. 



In the fifth section, Heteromera, there are 

 five joints in the first and second pairs of legs, 

 but only four in the third, (jig. 340). The 

 palpi, four in number, are large and projecting, 

 and the antennae, usually filiform or monili- 



Fig. 340. 



Blaps mortisaga, (Darkling-beetle). 



* Le Keux, Trans. Ent. Society, vol. ii. p. 24. 

 t Kirby and Spence, Introduce, to Entom. vol. i. 

 p. 185. 

 J Id. vol. iii. p. 683, 4. 



Creophilus marillosiu, (Rove-beetle). 



the body is elongated, and terminated by two 

 exsertile papillae, the elytra short, quadrate, 

 and often covering only the meso- and meta- 

 thorax ; the true or posterior wings, folded be- 

 neath the elytra; head broad and flattened, 

 mandibles large, hooked, and pointed, antennae 

 often enlarged towards their extremities, and 

 the tarsi of all the legs five-jointed. The 

 larvae are active and voracious, and undergo a 

 complete metamorphosis. 



The situation assigned to this group of in- 

 sects by different systematists has varied con- 

 siderably. Many authors have placed them 

 with the pentamerous insects, unto which from 

 their habits and number of joints in their tarsi 

 they appear to belong. Thus Dejean assigned 

 them a position between the Hydradephaga 

 and Phylhydrida ; Dr. Leach* between the 

 Silphida and Dermestid<e ; Mr. Kirby, in his 

 recent work,t between the Adephaga and 

 Necrophaga; and, lastly, Mr. Westwood J 

 between the Dermestida and ByrrAujfe On 

 the other hand Mr. Stephens, after Linne" and 

 Fabricius, has placed them at the end of his 

 Coleoptera, thinking, probably, as Mr. Kirby 

 has remarked, that they are connected with the 

 following orders, Dermaptera and Orthoptera, 

 by their abbreviated elytra, and by their anal 

 papillae or styles ; as they are also, probably, 

 by the shortness and structure of their alimen- 

 tary canal, which in many respects as much 

 resembles that of the ForfculieUe or Bfettufe, 

 as the Adephaga or Necrophaga. 



Order II. DERMAPTERA. 



Wings four, anterior ones (elytra) crustace- 

 ous, quadrate, and divided by a straight suture ; 

 not employed in flight ; posterior ones mem- 

 branous, folded longitudinally and transversely, 

 only partially covered by the elytra; anus 

 armed with large moveable forceps. Larva 

 active, resembles the perfect insect. Metamor- 

 phosis incomplete. 



The single family of this order, Forficulidtf, 

 (Earwigs) are readily distinguished from the 



* Article Entomology, Edin. Encycl. vol. ix. 



f Insects, Fauna Boreali -Americana, p. 85 et 

 seq. 1837. 



\ Introduc. to the Modern Classification of In- 

 sects, &c. 1838-9. 



