Invertebrate Gallery of the Indian Museum. 89 



ments known in succession as prothorax, mesothorax, and 

 metathorax ; and {3) an abdomen, formed of a varying 

 number— never more than ten— of separate segments. 



The head has the following " appendages ":—(i) a pair 

 of jointed antennae, (2) a pair of upper jaws usually form- 

 ed for biting or piercing, (3) a pair of jointed lower jaws, 

 often formed for chewing or piercing, known as maxillae, 

 and (4) a second pair of maxillae, which are usually fused 

 together to form a low^er lip or " labium". One or both 

 pairs of maxillae usually carry " palps" (maxillary palps, and 

 labial palps). Besides these true "appendages" there 

 also occur on the head a pair of large compound eyes, 

 and often also several small simple eyes or "ocelli", 

 and an unpaired "labrum," or upper lip, in front of the 

 mouth-opening. The dissection of the Cockroach (Case 

 70B), displays the structural details of the typical biting 

 and chewing mouth. 



In the Lepidopteya (Butterflies and Moths) the mouth- 

 parts are profoundly modified for sucking, the first pair of 

 maxillae being grooved and much elongated and closely 

 apposed to form a long suctorial tube, or " proboscis", and 

 the palps of the second pair of maxillae (labial palps) being 

 thickened and enlarged to form stout hairy cushions, be- 

 tween which the proboscis is coiled up when not in use, 

 while all the other mouth-parts are rudimentary — fsec the 

 enlarged drawing in Case 97C). In the Hymenoptera 

 (Bees, Wasps, Ants) the mouth-parts are adapted for both 

 biting and sucking or licking — (see the enlarged draw- 

 ing in Ca=e 97C). 



In the Uiptera (Flies) and Hemiptera (Bugs) the 

 mouth-psrts are modified for piercing and sucking, the 

 mandibles and both pairs of maxillae, and even sometimes 

 the upper lip, being greatly elongated for these purposes. 



Enlarged drawings of all the principal modifications of 

 the mouth-parts of Insects are shown in Case 9;C, the ho- 

 mologous parts being coloured alike throughout the series. 



The thorax in a typical adult insect bears the following 



