Vol. XXvii] ENTOMOLOGICAL NEWS. 303 



The Siphonaptera, or Pulicid group, forms a rather homo- 

 geneous order of insects, which has been considered as a sub- 

 order of the Diptera, by many investigators. They have be- 

 come sufficiently modified from the Dipteron type, however, 

 to be considered as representing a distinct order, although their 

 affinities are clearly with the Diptera, especially with the 

 Phorid group, which evidently resembles the ancestral group 

 which gave rise to the Siphonaptera. 



The Hymenopterous insects should be divided into two or- 

 ders, the Prohymenoptcra or Tenthredinid group, and the 

 Hymenoptera proper. The lines of descent of the Hymenop- 

 teroid forms are rather difficult to trace, and until more ma- 

 terial consisting of very primitive or annectent forms, is avail- 

 able, it will be very difficult to determine with any degree of 

 certainty, or satisfaction, the closest affinities of these insects. 



On page 347, of the Ent. News, Vol. 26, 1915, I made the 

 following statement : "The Hymenoptera very probably arose 

 from ancestors not very unlike those of the Isoptera and Gryl- 

 loblattids . . . this point, however, can be decided only 

 after a more extended study of the Hymenoptera, and an ex- 

 amination of intermediate forms not at present accessible." A 

 further examination of the primitive Hymenopteroid insects 

 (Lydidae, Xyelidae, etc.) has indicated that these forms bear a 

 strong resemblance to the Psocids, and certain features in 

 them suggest a relation to both the Meropid-Neuropteron line 

 of descent and the Blattid-Perlid line (to which the Isoptera, 

 etc., belong). The resemblance to the Meropid-Neuropteron 

 line is especially noticeable when the lower Hymenopteroid 

 forms are compared with certain Meropid insects, which I 

 captured in North Carolina, but have been unable to identify. 

 This resemblance to both the Blattid-Perlid group and to the 

 Meropid-Neuropteron, group is a rather puzzling feature, but 

 may possibly be explained by the fact that the Psocids, to 

 which the Hymenoptefa are related, also occupy a position in- 

 termediate between the Blattid-Perlid group and the Netirop- 

 tera, so that the Hymenoptera might also be regarded as some- 

 what intermediate between the two groups in question, al- 



