THE ENTOMOLOGIST. 55 



of the hitherto described species of Synergus have not been 

 clearly distinguished from each other. He has many proofs 

 that two certainly different kinds of lodgers live together in 

 one gall; and he gives in short the result of his observations 

 on C. lignicola. He isolated about four hundred galls of this 

 species. From most of these only the Cynips appeared ; the 

 rest gave the following results: — sixteen galls produced only 

 Synergus raelanopus ; two, S. raelanopus and a Eurytoma ; 

 twenty-eight, only S. Hayneanus; five, S. Hayneanus, with 

 S. raelanopus; two, only S. pallidipennis; three, S. palli- 

 cornis; one, S. pallicornis and S. melauopus; one, S. vul- 

 garis ; two, the Cynips and S. raelanopus ; one large gall 

 produced the Cynips, seven examples of S. raelanopus, and 

 one Eurytoma; four, the Cynips and S. pallicornis; and 

 lastly, two, a Pteromalus. In the galls from which the 

 Cynips and the Synergus appeared the cell of the first was 

 quite closed and normally formed, but the cells of the lodgers 

 were separate in the parenchyma. He mentions a gall of 

 C. cerricola, which afforded him in April nineteen examples 

 of S. thaumacera, and in May two of S. variabilis and three of 

 Eurytoma: these all came from one hole, the passage to 

 which was divided, and led from many chambers. It thus 

 seems that in general the contrivances of the lodgers cause 

 the death of the proprietor, for in sixty galls seven produced 

 the Cynips and the Synergus ; the latter only or the parasite 

 proceeded from the rest, and the imprisonment of the Cynips 

 by the Synergus was first observed by Spinola. Life in these 

 kinds of galls may be divided into two parts, — the inner life 

 and the outer life, — the first represented by the Cynips and 

 its parasites, the latter by the Synergus and its attendants ; 

 and the multiplying of the Cynips is not only limited by its 

 parasites, but by the Synergi in the outer life ; and in case 

 the latter are the victims of other parasites, their habitations 

 are not the less obstacles to the emergence of the Cynips ; 

 and the complications of life-forms in a gall are a little 

 epitome of biology generally, with regard to insects. Dr. Mayr 

 observes on the strangeness of the fact, and of its being 

 worthy of close study, that a Synergus lives in one kind of 

 gall three to four months, but in another kind a year or 

 more. The species which appear in winter are more nume- 

 rous than those which appear in summer, and those which are 



