NEUROPTERA. 175 



The lace-winged flies, ant-lions, etc., differ in impor- 

 tant characters from their parallel or representative 

 forms among the Odonata and Ephemeroptera, and 

 Packard has given an excellent summary of these dif- 

 ferences in his Entomology for Beginners (see pp. 

 84-87), accompanied by figures which illustrate the 

 facts. He speaks also of the primitive form of the 

 larva when compared with those of the remaining 

 orders. Though the mouth parts are much modified 

 as compared with the primitive biting type, especially 

 in the aphis-lions and ant-lions, there is an unques- 

 tionable resemblance to Thysanura in their larvae. 

 This indicates derivation from a primitive Thysanuroid 

 ancestor, through some intermediate winged insect. 

 What this intermediate winged insect may have been 

 it is difficult to determine with certainty. We have 

 for the present assumed that it may have been similar 

 to the winged ancestors of the orders X. to XVI., and 

 have designated it in Diagram IT. as B'. 



