162 



INVEKTEBRATE ANIMALS. 



" maxillary palpi " {mp). 4. A lower lip or " labium " {la), which 

 also carries a pair of jointed filaments, known as the " labial palpi " 

 (Ip). In the typical suctorial mouth, as seen in the Butterflies and 

 Moths (fig. 109, B), the following is the aiTangement oJ parts. The 

 upper lip and mandibles are quite rudimentary ; the maxillse {mx) 

 are greatly lengthened, and form a spiral tube fitted for sucking up 

 the juices of flowers ; and the labial palpi are much developed, and 

 form two hairy cushions, between which the trunk can be coiled up 

 when not in use. In many insects (fig. 109, C) the organs of the 

 mouth are essentially adajited for suction, but are also fitted for 

 inercing solid substances, such as the skin of animals or the stems 



;. 109. — Organs of the mouth of Inserts, enlarged ; (A) of a Beetle {Carahus) ; (B) of 

 the Small Cabbage White Butterfly (Pontia rajice) ; (C) of the Bed-bug {Cima: leciu- 

 lo.riits), the mandibles and maxillse being displaced to one side. I Labrum ; m Man- 

 dible ; Tttx Maxilla ; mp Maxillary palpus ; In. Labium ; Ip Labial palpus ; an Base 

 of one of the antennec. (Fig. B. is slightly altered from Westwood.) 



of plants. In these the lower lip forms a kind of sucking-tube or 

 sheath, within which are cuutained the maxillse and mandibles, 

 which are modified so as to form piercing organs or lancets. In 

 the common Bee the masticatory and suctorial types of mouth are 

 combined. The mandibles or biting-jaws are retained, to enable 

 the honeycomb to be manufactured, and there is also a tubular 

 trunk fitted for sucking up the juices of flowera. In the Butterflies, 

 too, in which the mouth of the adult is strictly adapted for suction, 

 the caterpillar is furnished with a masticating movith, so that it can 

 feed upon leaves, or other solid substances. 



The mouth in the masticating insects (fig. 110, a) leads into a 

 membranous and often folded cavity, termed the " crop " (b), from 

 which the food passes to a second muscular cavity or "gizzard " (c). 



