Vol. 1.] 



Woodivorth. — Wing Veins of Insects. 



135 



positive position very distinctly opposed to the latest study 

 on this subject, that of Comstock. 



The uniformity of structure makes it quite immaterial where 

 we begin the study of this venation. The order contains no 

 families with anything that may be called an ancestral vena- 

 tion connecting it in any peculiar manner with another group, 

 or showing how the peculiar venation of this order has arisen. 

 The only unusual forms are the reduced venations found in 

 several families, and the slightly increased venation of the 

 Tenthredinidse (Fig. 80). This group has been considered the 

 lowest in the series. Here, therefore, rather than in the groups 

 with reduced venation, may we hope to find suggestions on 

 the phylogeny of this venation type. 



The Tenthredinidte and Siricidte (Fig. 81) differ from all 

 other members of the order in the possession of an additional 



FIG. SI. Diagram of a Siricid wing. 

 Dotted line shows variable cross vein. 



FIG. 82. Venation of the Cynipidas. 

 Dotted lines are veins which may be 

 suppressed. 



posterior vein in the front wing, there never being more than 

 the merest rudiment of it in other families. They also some- 

 times possess additional cross veins, one in the neighborhood 

 of the stigma in the front wings, and a couple near the tip in 

 the hind wings; very rarely there is an additional independent 

 at the tip of the front wing. 



The parasitic forms show the extreme in the reduction of the 

 venation, where the only vein remaining may be the primary. 

 From this all conditions may be found up to the almost 

 complete venation of the larger Ichneumonida?. The Cynipidae 

 (Fig. 82) are peculiar in the great distance between the primary 

 and the margin, which is even more than is shown in Fig. 82; 

 when it alone is present, the appearance is very misleading. 

 The Proctotrupidse (Fig. 83) show best the range of venation 

 among this series of families. The Ichneumonida^ (Fig. 84) 

 show the suppression of the basal end of the anterior inde- 

 pendent. The Pelicinidse (Fig. 85) show a remarkable approach 



