200 Annals Entomological Society of America [Vol. XV, 



SUMMARY. 



1. A large series of hind wings, representing most of the 



important families of the Coleoptera, have been examined 

 and the following conclusions seem justified: 



2. The hypothetical primitive type of Coleopterous wing does 



not differ greatly from the Hypothetical type proposed 

 by Comstock and Needham for the Hexapoda in general. 



3. The hypothetical Coleopterous type is characterized by 



a fusion of R3 with R4 at the tip and by a similar fusion 

 of R5 and Ml. 



4. The usual cross veins are typically present. 



5. Modification of the venation goes hand in hand with an 



increase in the complexity of folding. 



6. In general there are two types of modification: 



(a) A pushing back of the primary venation toward the 



base of the wing and the substitution of secondary 

 thickenings in the apical area. 



(b) The reduction and breaking up of the veins. 



7. The types of venation fall naturally into four groups. 



(a) Represented by the Lampyridas which is the simplest 



type and may indicate the possibility of a Lampyrid- 

 like ancestral form for the Coleoptera. 



(b) Represented by the Cerambycid^ and Chrysomelidae 



in which R3 and R4 have become a simple cross vein 

 between R2 and R5, and where the primary venation 

 is cut off from the apical area. 



(c) Represented by the Carabidas which is characterized 



by the persistence of the fused portion of R3 and R4, 

 the presence of cross veins r - m, and the cutting of 

 R2+3 and R4 by the transverse fold. 



(d) A group of widely separated families where the 



venation is too highly specialized to show any 

 relationship. 



