Vol. XXVli] ENTOMOLOGICAL NEWS. 297 



The Lines of Descent of the Lower Pterygotan Insects, 



with Notes on the Relationships of the other Forms, 



By G. C. CRAMPTON.* 



(Continued from page 258) 



The interrelations of the different groups making up the 

 section Neuropteradelphia are extremely complicated, and can 

 be worked out in detail only after studying more of the primi- 

 tive and annectent forms than are at present accessible. Enough 

 material is available, however, to indicate the following rela- 

 tionships. 



The Raphidoides (Aponenroptera) or Raphidian group is 

 closely related to the Sialid group, but has tended to branch 

 off along its own line of development. The Sialoides (Mega- 

 ncuroptcra) or Sialid group comprises such insects as Sialis, 

 Corydalis, Chanllodcs, etc., and is one of the most primitive 

 of the Neuropteroid section, forming one of the main trunks 

 upon which the other lines of descent converge. This group 

 contains some of the largest of the Neuropteroid forms (hence 

 the name Meganeuroptera}. 



The Chrysopoides (true N euro pt era} or Chrysopid group 

 comprises such forms as the Chrysopidae, Hemerobiidae, Co- 

 niopterygidae, etc., and is rather closely related to the Sialid 

 group, the two together constituting the most primitive lines 

 of Neuropteroid insects. 



The Myrmeleonoides (Zygoneuroptera*) or Myrmeleonid 

 group is related to both the Sialid and Chrysopid groups and 

 has retained certain characters suggestive of a relationship to 

 the Zygoptera, or Libellulid forms. This group contains such 

 insects as the Myrmeleonidae, Ascalaphidae, Nymphes, etc., 

 all of which are quite primitive forms, so that it is rather diffi- 

 cult to determine which of the three groups (Sialids, Chryso- 

 pids or Myrmeleonids) is the most primitive, although the 

 Sialids are apparently as little modified as any. 



The Mantispoides (Dictyneuroptera) or Mantispid group is 

 related to the Chrysopid group, and also shows some affinities 



* Contribution from the Entomological Laboratory of the Massa- 

 chusetts Agricultural College, Amherst, Mass. 



