THE ENTOMOLOGIST. 505 



on the scene — that is a Eurytoraa — which contributes an 

 egg to the spangle, and thus a new complication begins ; but 

 the notice of this and of other agents may be deferred, including 

 the enquiry whether the Eurytoma lias the faculty of detecting 

 the previous visit of a Synergus, or whether it is indifferent in 

 this matter. The spangle, unless it is appropriated by a bird 

 or disposed of in some other way while on the ground, may, in 

 the ensuing spring, or afterwards, produce a Neuroterus, a 

 Synergus, or a Eurytoma; and, perhaps, the latter does not 

 interfere till the spring, and then inserts its egg into the gall, 

 or into the grub within the gall. In an oak-apple the pro- 

 prietor and the tenant live peaceably together, but it is 

 doubtful whether there is a sufficiency in a spangle for the 

 satisfaction of the Neuroterus and the Synergus together. 

 Tliere are sometimes millions of these spangles on one oak, 

 and the result may be imagined if each were to produce a 

 Neuroterus. Two other insects now also occur beneath the 

 oak-leaf: one scale-like, and of the Coccus tribe; the other 

 a little larva, which runs about quickly in search of Aphides 

 to devour, and is one of the Hemerobidae. — Francis Walker. 

 Note on the Appearance of Aphis Npnphcece and of its 

 Aphidius in the middle of August. — At this time numerous 

 whitish specks occurred over the leaves of the water-plaintain 

 on the border of a pond. These specks were dead Aphides, 

 which perished b}' means of Aphidii, and were not defended 

 by the presence of friendly ants. The living Aphis was 

 abundant, and was sometimes on the stalks of the leaves 

 beneath the water : these stalks were also inhabited by many 

 little leeches, and swarms of Achorutes aquaticus sometimes 

 occurred there. Excluding some of the Aphides on the 

 pond, the rest may be reckoned at about 100,000 in number, 

 and the Aphidii at about 10,000. A small individual, of a 

 species of Allotria, was with them. I observed above 100 of 

 the Aphidii, and they varied much in size. There is much to 

 be ascertained in the history of this Aphidius : its continuance 

 during the winter, the rate of increase, the number of broods 

 yearly, whether it is peculiar to A. Nymphaege or resorts to it 

 from other Aphides, and in that case whether its appearance 

 is altered by the variation of its food. A. Nymphaea) only 

 infests water-plants, and therefore there is not much occasion 

 to diminish its numbers ; but some one may have a fancy to 



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