152 



FIELD ZOOLOGY. 



the young ichneumons, whose one mission in Ufe would 

 be to dispose of at least one young horntail apiece. 



All members of the order have four clear, membran- 

 ous wings, destitute of scales. The front wings are larger 

 than the hind wings and bear the brunt of the flight 

 activities. In the butterflies and the moths, the wings 

 on each side of the body are fastened together either by a 

 hook, by bristles, or by a pronounced curve of the front 



border of the hind wing. 

 The beetles, the grasshop- 

 pers, and the bugs use 

 only one pair of wings for 

 flying, hence do not need 

 to provide for the interac- 

 tion of the wings. But in 

 the hymenopters we come 

 again to insects with four 

 wings, all used for flight; 

 and some means of syn- 

 chronous action is neces- 

 sary. If a honey-bee's 

 wings are examined care- 

 fully it will be seen that it 

 is very difficult to separate the small hind wing from the 

 larger front wing. With a good hand lens, better with 

 the microscope, there will be found a line of hooks fasten- 

 ing the hind wing to the front wing, fitting over a strong 

 vein at the hind margin of the front wing. 



The first abdominal segment is usually fused with 

 the thorax, and that means that the small segment which 

 forms the articulation between the thorax and the abdo- 

 men is usually the second abdominal segment. This is 

 especially true in the wasps and the ants. 



Fig. 6o. — The pigeon horntail, Tremex 

 columha. A, imago; B, larva (with para- 

 sitic larva of Thalessa attached). (Nat- 

 ural size. Folsom, after Riley.) 



