248 ^ [Septkmuki'. 



1. Are CYNIPS Q. INANIS, C. Q. COCCINE^ and C. Q. SPONGIFICA onk 



and the same species? 



We have seen above, that these gall-flies are so similar that I could not 

 find any important characters to distinguish them. Still, it does not fol- 

 low hence that such characters do not exist. The comparison of a larger 

 number of specimens would probably lead to their discovery. 



The supposition that they arc the same species would involve another 

 one, that the difierence between the galls described under the above names 

 is merely due to the organic reaction of difl'erent kinds of oak against the 

 sting uf one and the same insect. It is obvious however, that this last 

 supposition must be dropped if it is proved that C. q. cocci iicse and ('. q. 

 iiKinia both occur on Q. coccinea^ of which, as shown already, I am as yet 

 uncertain. 



Another fact apparently proving that they are really different sj)ecies, 

 is the close resemblance of C. q. cwlchs % to the male of C. q. spoinjifica. 

 The former is only smaller, othexnvise it does not differ from the latter more 

 than the females of the three species in question differ from each other. 

 Now ('. q. Calebs seems to be undoubtedly a different species, as its spin- 

 dle-shaped gall occurs also on a species of oak about which I am uncer- 

 tain whether it is (J. coccinca or ruhra. Thus we have three different 

 galls, occuring, at the utmost, on tu-u kinds of oak, so that, by all means 

 two of the galls, and perhaps all the three grow on the same kind of oak. 

 It seems obvious, hence, that gall-flies, however similar they may be, must 

 belong to different species if they produce difl'erent galls on the same tree 

 and that, at the same season. iMr. Ratzebvirg (in his work: Forst-lii- 

 sectcii) asserts, from personal observation, that a species of Cjuips pro- 

 duces the same gall even on different kinds of oak. The europeau ('./<■- 

 cnnddtrlx of the Qiicrcus pedunculata gave this result, when it attacked 

 some american oaks in his garden. 



For all these reasons, I believe, therefore, that 6'. q. iiianis, coccinae, 

 spomjljica and coelcbs are different, although closely allied, species of the 

 same genus. 



2. Have the Gai.l-Flies of the Oak-Applbs one ok two ckxi; rations y 



If they have but one generation, what becomes of the gall-flies escap- 

 ing in June and the larvae of which begin to develope nearly a year later, 

 in the buds of the following spring? They may lay their eggs in the buds 

 destined to be developed on the next year, which eggs may remain dor- 

 mant, till the buds begin to grow. But this remains to be proved. 1 do 



