CHAPTER XXIV 

 INSECTA (continued) 



Order VII. : HYMENOPTERA (ANTS, BEES, WASPS, AND 

 GALL-FLIES) 



General THIS order is one of the largest and most highly 

 Character- developed of all the Insecta. In structure, all are 



istics. alike in possessing four transparent, relatively 

 small wings with few nervures. The two wings on either side 

 are held together by minute hooks, so that, in flying, two 

 wings function as one (Fig. 291). The mandibles are large 

 and strong, being used not only for biting food and for carry- 

 ing, but also in excavating and in shaping the cells for the 

 young. In some Hymenoptera, a special proboscis formed 

 from the other mouth-parts is also present which is used in 

 obtaining food, as in the Bees. 



In all of them the front " thoracic " mass of the body is 

 formed, not only of the three thoracic segments, but also of 

 the first abdominal segment which is more or less fused with 

 these. In many the second abdominal segment forms the 

 " petiole," or constricted waist-segment, behind which comes 

 the "gaster" or hind body, usually spoken of as the abdomen, 

 though the name is not strictly applicable, any more than it 

 is strictly correct that the fore body should be termed the 

 thorax, since it includes one abdominal segment. However, 

 to avoid multiplication of technical terms, the whole fore 

 body will here still be called the " thorax," the inverted 

 commas indicating that the term is only adopted and riot 

 rightfully possessed. In the adult, the number of segments 

 in the body is variable, but in the larva there are thirteen 



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