ARMATURE IN THE EUROPEAN RHOPALOCERA. 361 



incurved, and gradually approaching backwards till they meet and join in the apical half 

 (PL LV. fig. 9, dissected). 



The standard form of the tegumen is that in which, looking from above, the organ is 

 much longer than broad, and tapers from a moderately broad base to a moderately sharp 

 apex, and, looking from the side, when the apical half gently curves downwards and 

 the side lobes are well but not inordinately developed. The standard length is that in 

 which the tegumen slightly exceeds the harpagones, when viewed from the side and the 

 parts are in their normal position. As will be seen, there is often a very considerable 

 departure from this typical form. 



4. Modifications of the Tegumen in the various Families. 



Papilionid^. Structure very abnormal. In Papilio it is not visible without dissec- 

 tion, and is shortly triangular and deeply emarginate — in fact, almost bilobed (PI. LVL 

 fig. 39 b). As pointed out above, the upper margin of the last segment assumes the 

 character of the tegumen, and the tegumen proper appears in the character of the side 

 lobes (PI. LVL fig. 40 a & b). In Thais the construction is somewhat on the same plan as 

 in Papilio, but the last segment is less tegumen-like (LVTI. figs. 1 & 2). In both these 

 genera I at first was deceived by the form assumed by the apical segment. In Pamassius 

 the tegumen is larger, but various in form. In P. Apollo (PI. LVTI. figs. 3 b & c) and 

 P. Delius the apex is short and slightly developed, and the side lobes (or what appears 

 to be them) are exceedingly developed, and on the same plane as the apical lobe. In 

 P. Mnemosyne the structure is rather different : the apex is bilobed, resembling the 

 side lobes in the other species; and the side lobes proper are smaller and situated 

 below. 



Pierib^. Structure various. Side lobes obsolete or very slightly developed. Tegumen 

 rather short, acuminate-triangular, with entire apex (PL LVL figs. 27 b, 30 b, & 37 b), 

 or somewhat bifurcate (PL LVL figs. 31 c, 34 e, & 38 b). 



Lyc^enid^e. Structure still further modified, the development of the part being rather 

 in a lateral than a longitudinal direction. In Theela (PL LVII. figs. 4-8), Aurotis (PL 

 LVII. fig. 9), and Thestor (PL LVII. fig. 10), the tegumen may be regarded as decidedly 

 transverse and broadly developed laterally ; and in these genera it is relatively much 

 larger than the other parts. In Lycmna (PL LVII. figs. 11, 12, & 13) the development 

 is still decidedly but more narrowly lateral. In Polyommatus (PL LVII. figs. 14-24), 

 while in some species the development is transverse, in the majority it is more longi- 

 tudinal, the sides, however, and not the centre, being produced. P. Alsus (PL LVII. 

 fig. 24) is an exception, as in this species the greatest development is in the direction of 

 the mesial dorsal line, as we find in the type. 



In this family the side lobes are frequently present, but, instead of arising from each 

 side of a central prolongation, spring from the under and inner side of the lateral prolon- 

 gation (PL LVII. figs. 7 b, 10 a, 12 b & c, 19 b, &c). In P. Alsus (PL LVII. fig. 24 a) 

 their situation is more normal. 



Erycinid^;. Short and broadly triangular. Side lobes developed, but nearly hidden 

 (PL LVL figs. 26 b & c). 



