THE WIXuS OF IXSECTS 



-107 



extends towards the base of the wing. Both of these eonditions has been 

 reached in the most generahzed of H\-ing Hxniienoptera. 



The existence of this method of speciaHzation in the H\niienoptera and 

 the extent to which it has been cairied in this order were tirst recognized 

 after an understanding of the methixis of modi lica lion of tlie wings of the 

 Diptera had been attained. Fortunately among the Diptera there are to 

 be found examples of all degTccs of this method of coalescence of veins; 

 reference to some of these will be made later. 



In the M\-niono])tora. the hind wings are extremely nioditied, even in the 



Fii:^. 4J,V — Willies of Panil^hilius. The \rins ixw \v\.W\\\\. 



most generalized members of tlu' order; on this accoimt only fore wings of 

 Hymeno])lera will be stiulird in this introductory lunirse. 



Among till' more generalized wings oi llymenoi)lera are those of (he 

 genera Pamphilins and Macroxycla, (wo genera of saw-(lies. in eai"ii of 

 these genera there is i)n'ser\-ed in (he fore wings all of the primidve wing- 

 veins with a single excei)tioii; and as in each it is a dilTeren{ \ein (hat has 

 been lost from that which is lacking in the other, b\- slndying wings of the 

 two genera all of the wing-\'eins can be obser\cd. 



Figtu'e 423 represents (he wings of /'a;;//'///7//^s•,■ in (his ligm'c (he \'eins 

 arc lettered. Figure 42.1 represents (he wings of a Macrowrla: in this 

 figm-e the cells are lettered. In i\uiif>ltiliiis vein R- of the fore wings is 

 lacking, biU (his x't-in is i)rt"st'nt in .'l/(j(:r('.v.vc/(i.- on (he otlu-r hand, in 

 Macroxycla \ein (Hi- of (he fore wings is lacking, but this \ein is pri'Si'nl in 

 Pa»if>liiliiis. 



