192 Annals Entomological Society of America [Vol. XV, 



perhaps partly due to the fact that these organs are hidden 

 from view beneath the elytra and cannot be studied without 

 relaxing dried specimens, and partly due to the fact that the 

 homologies of the wing veins of this order have never been 

 thoroughly worked out. It is the object of this paper to show 

 in a preliminary way some of the neglected possibilities of these 

 organs in the taxonomy of the group, and to show how the 

 venation of the Coleoptera may be homologized with that 

 of other orders. In this study a large series of wings, rep- 

 resenting the most important families of the order, has been 

 examined, but the work is still far from complete. 



On examining a series of Coleopterous hind wings, several 

 general outstanding features are apparent. First, that there 

 is a distinct type of venation characteristic of the order. This 

 is remarkably constant when the size of the group is considered. 

 Second, there is considerable similarity between the venation 

 of beetle wings and that of other insect orders, indicating the 

 common origin of winged insects. Third, that within the 

 order Coleoptera there are several types of modification which 

 may have phylogenetic significance. 



A study of the literature, however, fails to reveal any com- 

 prehensive investigations presenting conclusive evidence as 

 to the homology of the wing veins of Coleoptera with that of 

 other insect orders. 



THE RELATION OF FOLDING TO VENATION. 



One of the most striking features characterizing the wings 

 of the Coleoptera is the fact that they are not only folded 

 longitudinally, but also have at least one definite transverse 

 fold. The advantage to the insect of this type of folding is 

 obvious as it results not only in narrowing, but also in shortening 

 of the wings when these appendages are folded against the 

 body. This brings the wings under the elytra for protection. 

 This protection is particularly essential to an insect of retiring 

 habits living in places where an unprotected wing membrane 

 would almost certainly be torn. 



The fact that these folds or furrows necessarily follow the 

 lines of least resistance between veins, usually running parallel 

 with, and often very close to a vein, led Woodworth to associate 

 them with the formation of veins. There is obviously some 



