The Scottish Naturalist, 155 



not abound — not .even occurring in the same wood, which was a 

 small one — and in three weeks after in the self same spot I 

 found a fresh gall. It seems to me then clear that Adler's 

 hyjDothesis is erroneous, and not consistent with fact. 



If no alternation of generations takes place, it is evident that 



the eggs of the vernal species must lie dormant for 9 or 10 



months. That they are laid in June (or probably May in some 



places) is certain from our never finding the flies before the 



appearance of the galls in the spring, and by bred specimens only 



living a day or two after leaving the galls \ and again we find 



their dead bodies in spiders' webs, &c., in June, while I have 



observed T. megaptera in copulation at the end of that month. 



The fact of the eggs lying so long dormant is rendered more 



extraordinary by the galls in many cases not appearing till the 



leaves or flowers, as the case may be, are fully grown. But in 



reality there is nothing more strange in this happening with S. 



baccaru77i, than that the "^ spangle " galls should appear in the 



summer, remain flat and dry without a trace of the insect inside 



during the autumn and winter, then in the spring swell up, 



become soft and succulent, the larva inside growing rapidly, 



and in the course of a week or two emerging in a winged 



state. 



From the extreme sluggishness of these creatures, as well as 

 from the very short time they live as imagos, observations on 

 their oviposition are very difficult to make. I have only once 

 observed it. This was with Aphilothrix albo-pimdata, on 25th 

 April ] the galls followed early in June, and as this species 

 becomes developed in the autumn it must hibernate in the 

 perfect state. This is also the case with D. divisa and other 

 agamic forms. 



The gall-making Cynipidse are most sluggish in the perfect 

 state. I have only once observed them fly, that being with 

 some specimens of A. radicisy which were bred in the house, 

 and whenever the box containing them was opened, they flew 

 into the gas. (I put some specimens of radicis into spirits for a 

 week, and they revived when taken out and dried.) 



From the above remarks it is plain that the " Alternation of 

 Generations " of Adler is nearly the same as the " Dimorphism " 

 of the late B. Walsh. According to Walsh, Cynips spongifica, 

 O.S. raises " oak apple " galls on Qiiercus tmdoria, which 

 become fully grown about the middle of June, and from a small 

 proportion of the galls emerge $ and ? flies ; the remainder 



