HIPPODAMIA. 



29 



Quite a different line of development is occasioned by the appearance of 

 spot e, the crescent-shaped mark just cephalad of 3 (fig. 16, nn, w, etc.). 

 This is the essential feature in the variety extensa, but may be seen with 

 various patterns so far as the rest of the elytron is concerned. Ordinarily 

 pigmentation not only makes spot e confluent with spot 3, but is so profuse 

 as to hide spot e entirely (fig. 16, zz). For this reason I am uncertain 

 whether spot e is invariably present in the true variety quinquesignata. 

 I suspect it is a necessary character, without which 1 and 3 would fail to 

 coalesce or coalesce only as in Nos. 421 and 427. Where 4- is confluent with 

 3, e is often present, but there are cases where it is clearly not present 

 and others where its presence is doubtful. Where e is present and pig- 

 mentation increases, confluence with 1 may result to form variety quinque- 

 signata (fff) . If 1 is absent, the pigment projects laterad to an acute angle 

 (uu), the condition given the name extensa by Mulsant when other spots 

 are absent. 



Still another line of development is dependent on the appearance of 

 another new spot which I call q, just laterad of spot 3 (ff) . It is very 

 rare that where q is present it is not so widely confluent with 3 as to cause 

 the impression that spot 3 is simply produced laterad (ii) . Such was my 

 original conception. Another spot, q', may carry the pigment still farther 

 laterad. It may even coalesce with 2, but the tendency is not a strong one, 

 for the pigment frequently stops short of it, with a narrow line of the 

 ground-color intervening. 



Confluence of q with i and of q and q ' with 1 is seen very rarely. Spots 

 4 and 5 are generally larger when q is present, and 4 is frequently squarish 

 in outline. This makes it possible that we have in variety quindecim- 

 maculata and its allied varieties a distinct species, although that view is 

 not here adopted. 



Spotless elytra are most frequent in the non-mountainous and non-humid 

 sections of the Pacific States. Specimens from Onaga, Kansas, sent me 

 by Mr. Crevecoeur, show the absence of several spots. Reduced pigment 

 is also known from Phoenix, Arizona, and Black Hills, South Dakota. I 

 suspect the specimens from the Black Hills were obtained from the plains 

 around the Black Hills rather than from their higher portions, as we have 

 the mountainous varieties also reported from the Black Hills. Apparently 

 the Pacific Coast area of the variety obsoleta extends through Arizona to 

 the Great Plains, where it exhibits itself more largely in transitional in- 

 dividuals. 



TABLE 7. Number of spots in Hippodamia convergent. 



