Kinsey: Studies of Cynipidm 



39 



region, in the same faunal area, but on another host, Quercus 

 agrifolia. This variation in these cynipids exactly parallels 

 the variations of the two oaks which are the hosts. As to the 

 status of these two oaks Jepson states: (1910, Mem. Univ. 

 Calif., II, pp. 230, 231), ''While the two species are thus very 

 distinct [in the north], frontier stragglers are not always 

 readily separated. The leaves of the Coast Live Oak [Q. 

 agrifolia] are sometimes quite flat [as is normal in Wislizenii] 

 and the terminal winter buds on fruiting shoots of Interior 

 Live Oak [Q. Wislizenii] may remain dormant so that full 

 grown acorns may appear to be on 'one-year-old' wood [as is 

 normal in agrifolia]. Acorns removed from the branch or 

 picked from the ground are sometimes not determinable, so 

 much do certain deep-cupped forms in the two species re- 

 semble each other. Nuts short and thick or as slender as a 

 quill are not uncommon variants in Quercus Wislizenii acorns. 

 These variations, which are to a large extent a matter of 

 nutrition, are closely matched by similar variations in Quercus 

 agrifolia. While the Interior Live Oak [Wislizenii] in tree 

 form [as in the north] trespasses little if at all upon the Coast 

 Live Oak or Encina [agrifolia] territory, it is found through- 

 out the same region, overtopping it, as it were, on the summits 

 of the mountains as a low shrub [as in the south] ." 



One explanation that may be offered is that distinctus has 

 been segregated from other varieties by isolation upon a dis- 

 tinct host, much as geographic isolation would allow the de- 

 velopment of distinct forms. In the Sierras where the hosts 

 of the two are distinct, the two varieties do not interbreed, 

 but at more southern points the two hosts, being more closely 

 related, sometimes fail to effect the requisite isolation, and 

 some degree of interbreeding may occur. A single gall from 

 the many I collected near Santa Barbara gave adults which 

 have an areolet fully as large as in any specimen of distinchts, 

 tho in many respects the characters are those of macu- 

 lipennis. I recorded this material as from agrifolia, but it is 

 not impossible that I misdetermined a single tree of Wislizenii, 

 since dwarfed specimens of the two oaks are so similar in the 

 region. 



In the northern Sierras, north of El Portal, in another 

 faunal area, galls of this species occur on Q. Wislizenii which 

 are somxetimes shaggy as in variety distinctus and sometimes 

 entirely smooth. Sometimes both forms occur in close prox- 



