34 donaldson bodine. 



The Specialized Frenat^. 



The Specialized Frenat?e are divided into two groups : the Micro- 

 frenatfe and tlie iNIacrofrenatre. The Microfrenata include those 

 moths in which " the anal area of the hind wings is not reduced, 

 having usually three anal veins, except in certain minute forms where 

 a broad fringe has been substituted for the membrane of this area." 

 The group comprises the superfamilies Pyralidina, Tortricina, Tineina 

 and the family Sesiidie. The antenme of the members of this group, 

 w'ith the exception of the Sesiidie, are quite constant in structure, 

 and can generally be separated from any other Lepidoptera wdth 

 great ease. The only forms which might cause any difficulty are 

 among the Geometrina in the family Sterrhidse. The separation of 

 certain species of the genus Acidalia from the Microfrenatse will re- 

 quire some experience on the part of the analyst, nevertheless the 

 antennse of the Microfrenatse, with the exception noted above, indi- 

 cate that the group is a definite one. 



We are unable to find constant structural characters in the an- 

 tenna3 which are peculiar to the several families constituting the 

 group. There are characters, however, which throw much light upon 

 their relationships. Tiie antenna of a Pyrausta oxydalk may be 

 taken as typical of the Pyralidina. The clavola is long, slender and 

 filifonn, composed of many segments all of which are quite similar. 

 Where there is any dissimilarity, the segments of the proximal por- 

 tion are not so specialized for the increase of the sensitive surface, 

 but are better adapted for the support of the distal portion. Fig. 

 47 represents a typical segment. The arrangement of scales, the 

 position of the cones, the pits with their conspicuous circle of guard- 

 ing i)oints, the ventral expansion of the segments, all are features 

 prac'tically constant in the whole superfamily ; in fact, with little 

 modification of some ])arts, they are constant in all three super- 

 families. The constant and ])eculiar character of the three super- 

 families, however, is the division of the chitin surface into areas by 

 thin })lates normal to the surfiice. The peculiarity of the condition 

 in the Microfrenata^ is that, however the shape of the included areas 

 may be varied, the bounding plates are continuous, and the general 

 surface remains even, see Figs. 34, 35 and 36. As already stated, I 

 believe the difierent shaped areas are all modifications of the hex- 

 agonal form and represent difiereiices in degree only, not in kind ; 

 yet as a rule, the limits of each sui)erfamily are sufficiently separated 



