48 Psyche [June 



most part, contented themselves with merely describing the parts, 

 without comparing them with other insects, the homologies here 

 proposed must be regarded as purely provisional, until more inter- 

 mediate stages can be obtained in order to determine what paths 

 of development have been followed in arriving at the different 

 types of genitalia here represented, or until suitable material can 

 be obtained for dissections which cannot be carried out with dried, 

 borrowed material, or from single specimens, upon which I have 

 been largely dependent! On this account, it is to be hoped that 

 those who have specialized in these groups, and therefore have 

 access to a wider range of forms and more favorable material, will 

 carry out a more extensive study of the genitalia, in order to ar- 

 rive at a definite conclusion concerning many of the points which 

 a lack of suitable material has made it impossible to determine. 



It is quite generally conceded that the Sialid group should be 

 rated among the most primitive representatives of the order 

 Neuroptera.^ I have therefore selected CorydaUs, Chauliodes and 

 Neuronia (which are the most instructive representatives of the 

 group, available to me) as the basis for a comparison with the 

 higher forms here discussed. In these insects (Figs. 4, 10, and 

 15), the digestive canal opens through an anal tubercle called the 

 tuberculum, anoppilla, or proctiger "ap." The two plates labeled 

 "pa," one on either side of the tubercle "ap," were called par- 

 oprods in a previous discussion of the parts in Neuroptera (Cramp- 

 ton, 1918), although I am not positive that they are the exact 

 homologues of the paraprocts, or parapodial plates, of the Orth- 

 optera and lower insects. In CorydaUs (Fig. 15), the plate "pa" 

 bears a pair of appendages "g," usually referred to as the superior 

 and inferior appendages of the gonopods. For the sake of brevity 

 they may be termed the surgonopod and subgonopod. The upper 

 appendage, or surgonopod (Fig. 15) is the larger of the two, and 

 appears to be the one to persist, when one of the two appendages 

 is lost (as in Fig. 10, etc.). 



Klapalek, 1903 (Bull. Int. Acad. Sci. Boheme), thinks that the 

 gonopods of adult Trichoptera, etc, correspond to the "Nach- 

 schieberti'' (anal prolegs.*) of the larva. The gonopods of Neu- 



1 A study of the thoracic sclerites (which offer the most important characters for determining 

 the relationships of insects) would indicate that the Neuroptera form a homogeneous group, 

 which should not be further divided into " orders." 



