1892.] ENTOMOLOGICAL NEWS. 27 



Following in the other direction through tenuisignata (9), 

 marginipennis (10), Hentzii (n), sexguttata (12), heemorrJiagica 

 (13), and splendida van (14), it will be observed that through a 

 gradual thinning or absorption of the markings, or by their 

 fragmentation and obliteration we arrive at the opposite result of 

 elytra without any white markings whatever, as in many forms 

 of obsoleta, scutellaris, pimdulata and hczmorrhagica. 



Those species which vary from the type in having the markings 

 broken into spots, as iz-guttata or Hentzii, may lose the spots 

 by a gradual decrease of size, so that they all seem to disappear 

 nearly at the same time, or the spots may disappear successively, 

 those on the disc being the first to go, while the marginal spots 

 remain. 



From our series it would be difficult to say which spot is the 

 most persistent, but it is probably the apical lunule, as there are 

 more with entirely dark elytra with slight traces of this spot than 

 with any other, as shown in abdominalis z\\& punctulata. 



Forms like lemniscata (16) seem very far removed from the 

 type, but many forms of imperfecia (15) show how the markings 

 gradually leave the margin and tend by fusion to form a vitta at 

 first somewhat oblique, but finally becoming nearly median. 



The last two figures on the plate represent the markings of 

 Gabbii (17) and Saulcyi (18), in which the ends of the bands or 

 lunules are greatly prolonged. The latter form, which represents 

 dorsalis as well, is but rarely seen so perfectly marked, the ten- 

 dency being toward a greater extension of the white. The other 

 species is scarcely variable, although equally a coast form. 



Those species which retain a permanent divergence from the 

 normal standard, such as togata (6) or lemniscata (16), are doubt- 

 less descendants from a normal type which has varied, and in 

 which a variety has become isolated and perpetuated itself. 



One result of an examination of my species with ideas here 

 explained has been the discovery that C. lunalonga Schaupp is 

 merely a variety of pusilla with markings a little better defined. 

 Specimens before me establish the lead very distinctly. 



In view of all the facts here presented the question mi-lit be 

 asked, why do some species vary while others do not ? \Yhilc 

 this matter is worthy of some thought, it is not pos>il>K' to ^ive 

 a satisfactory answer. Some species doubtless vary from climatic 

 causes. A notable instance will be seen in hui/ion-lhi^ica, which 



