142 PROC. ENT. SOC. WASH., VOL. 21, NO. 6, JUNE, 1919 



belong to the "Strophandria," or sawflies which exhibit a torsion 

 of the genital apparatus. The interpretation of these resem- 

 blances, however, depends upon the character of other structures 

 as well as the genitalia, and the condition here mentioned is 

 referred to merely to indicate a line of investigation which might 

 possibly lead to some interesting results in connection with the 

 study of other structures in addition to the terminal ones. 



In all of the siricids which I have been able to examine, there 

 are small spine-like projections near the tip of the copulatory 

 ossicles "gl" of Fig. 53. Similar ossicular spines occur on the 

 region labeled "gl" in Tremex (Fig. 36), and I would therefore 

 interpret this region as the homologue of the copulatory ossicles 

 (i. e., the region "gl" of Fig. 36), although it is not demarked 

 from the sclerite "pal" (Fig. 36). 



The copulatory ossicles "gl" are small in most of the lower 

 sawflies (Figs. 32, 33, 28, etc., and in Megaxyela (Fig. 28) they, 

 and the region "pal," have become folded inward, and come to 

 lie on the mesal surface of the base of the forceps "gb," making 

 it very difficult to detect them in this hidden location. This con- 

 dition may have been due to a shrinking of the parts in the dried 

 specimen of Megaxyela which I examined; but since I was able to 

 study only one representative of these rare insects (males of 

 which are extremely scarce), I am unable to state whether this 

 condition would occur in "normal" specimens, or those not 

 shrunken by drying, although I suspect that this infolding would 

 not occur in fresh material. 



The processes labeled "pa" in Figs, i, 2 and 3, and the plates 

 labeled "pa" in Figs. 4 and 5, do not occur in those xyelids, 

 "lydids" (pamphilids) , xiphydriids, cephids and siricids I have ex- 

 amined, and appear to be a modification developed in the "twisted 

 genitalia" group alone, although they are not developed in all 

 the members of this group. Even in the comparatively highly 

 modified genitalia of such forms as Cephus (Fig. 8) among the 

 "non-torsion" group there is no marked tendency for the basal 

 segments of the forceps "gb" to unite; but in the members of the 

 "torsion group shown in Figs. 10, 12, 13, etc., the basal segments 

 of the forceps "gb" become rather closely approximated, and in 

 such forms as Perga (Fig. 9) there is a marked tendency for these 

 basal segments "gb" to unite, and I should be inclined to interpret 

 such a union as representing a rather high degree of specializa- 

 tion or departure from the primitive condition. 



The "gonocondyle" labeled "b" in Figs, i, 14, 24, etc., appears 

 to be better developed and more elongate in the "torsion" group 

 of sawflies (i. e., those in which a torsion of the copulatory ap- 



