INSECTA. 



Fig. 375. 



Anterior and inferior views of the mouth and head of 



Anthophora retusa. 



A, antenna ; b, epicranium and ocelli ; c, cor- 

 nea ; d, clypeus anterior ; e, labruin ; f, mandi- 

 ble ; g, the maxilla; h, its palpus; i, feeler- 

 bearer or part of the ligula ; h, labial palpus ; /, 

 mentum ; m, sub-mentum ; 1, cardo of the maxilla ; 

 2, stipes ; 5, the lacinia or blade ; *, ligula; **,pa- 

 raglossce, its lateral lobes. 



daceous genera, the Tenthredinida and Ves- 

 pidtE, the clypeus posterior seems to have be- 

 come entirely obliterated, unless we regard the 

 broad clypeus in these insects, as in the Hornet, 

 the posterior one, and the plate concealed be- 

 neath it, within the mouth, to which the 

 labrum is attached, as the anterior. But we 

 are not inclined to do this, because in some of 

 the Ichneumonid< and Sphecidte a trace of the 

 clypeus posterior remains a little anterior to the 

 antennae. In Ichneumon Atropos the clypeus 

 is narrowed and depressed in its middle, as if 

 originally formed of two parts, while in Ammo- 

 phila vulgaris the clypeus posterior is clearly 

 indicated as a minute triangular plate situated 

 in the middle line, immediately beneath the 

 insertion of the antennae, and it exists in a 

 similar form in some of the Apida, as in the 

 large female Bombus lapidarius, and in some 

 specimens of Anthophora, the clypeus posterior 

 being in all instances bounded by a trace of the 

 triangular suture. The labrum (c) is always 

 distinct, but variously formed. In Vespidte it 

 is narrow, acute, and hidden beneath the ante- 

 rior clypeus; in the leaf-cutting bees, Mega- 

 chile, it is narrow and quadrate; but in the 

 hive and humble-bees it is large, and rounded 

 at its anterior margin. The mandibles are sub- 

 ject to considerable variation of form.* In 



* See Essay on Fossorial Hymenoptera, by W. E. 

 Shuckard, p. 12, et seq. 



some, as in Ammophila, which burrows in the 

 sand, they are long, hooked, and furnished 

 with but a single tooth at the apex, without 

 cutting edges ; and they are of somewhat the 

 same form in Anthophora (fig. 375, f), whose 

 habits of life in this respect are similar. In the 

 Vespidte, which gather the materials for their 

 nests by rasping off little packets of fibres from 

 decaying wood, they are broad, triangular, and 

 armed along their edges with strong teeth ; and 

 such is also their structure in Anthidium mani- 

 catum, which scrapes off the down from the 

 woolly stems and leaves of plants for the same 

 purpose; while, in the hive-bee, which em- 

 ploys them in moulding the soft wax in the 

 construction of the combs, they are shaped at 

 the apex like a spoon, without indentations ; 

 their form in each instance being thus dis- 

 tinctly referable to the habits of the insects. 

 In the gregarious species there is also a dif- 

 ference in their form in the two sexes, those of 

 the males being often smaller and less curved 

 than of the females, or workers, and they are 

 always, particularly in the Bombi, more densely 

 covered with hairs. 



In the whole of theTerebrantia, Pupophaga, 

 and some of the Aculeata the mandibles are 

 still the chief cibarian organs ; the Athalia em- 

 ploys them in masticating the pollen of flowers, 

 and the maxillae and labium in sipping the 

 honey; while the omnivorous Formicidte and 

 Vespida employ them in tearing and masti- 

 cating their food, whether it be the pulpy sub- 

 stance of fruits, or the muscles and hard cover- 

 ings of other insects. In the Apida the chief 

 use of the mandibles is in constructing the 

 nest, while the maxillae and labium are the 

 only organs employed in taking food. In the 

 strictly carnivorous families the maxilla are not 

 longer than in the preceding Orders. In most 

 of these, as well also as in the Terebrantia and 

 Chrysidida:, the extremity of each maxilla is 

 obtuse, and divided into a distinct lacinia and 

 galea, and the palpi are long and six-jointed. 

 In the FormicidtE and Vespidee, which subsist 

 upon fluid as well as solid aliment, their length 

 is increased ; but in the true Apidte, which 

 subsist entirely upon honey, they are drawn 

 out to a great length, and, with the labium be- 

 neath, form a tube through which the aliment 

 is conveyed to the mouth, as in the hive and 

 humble-bees. In these species the cardo (1) 

 is long, slender, and formed of two parts, which 

 conjointly articulate with the stipes (2). The 

 longest of these, the basilar portion, has two 

 apophyses at its extremity, and is articulated 

 with the anterior part of the base of the cra- 

 nium, at the inner side of the articulation for 

 the mandibles, exactly as in Coleoptera; and 

 its muscles in like manner are attached to the 

 lateral and inferior parts of the head and orbital 

 plates. It is the lora, or lever of Kirby, which 

 enables the insect, by the additional articula- 

 tion of its second part with the sub-mentum, to 

 thrust out the maxillae and labrum together to a 

 great distance. The part that articulates with 

 the sub-mentum, the proper cardo of Kirby, is 

 very short in Bombus lapidarius, but of consi- 



