76 



THE ENTOMOLOGIST. 



Veil)", cler zool.-botan. Gesellschaft, Wien, xix. 559) — is but a 

 synonym of one of Giraud's own species, S. Hosculi (1868, 

 Ann. Soc. Ent. Fr. p. 54), as pointed out by Dr. Mayr. 

 Ceroptres arator, H., occurs in the gall as an inquiline, in 

 the summer of the same year. — E. A. Fitch. 



42. SpatJiegaster aprilinus, Gir. — This vesiculate gall, 

 normally about as large as a pea, is generally developed on 

 the terminal, rarely on the axillar, buds 

 I'ig. 4.2. of Q. pubescens, but it sometimes 



'•^ occurs on those of Q. sessiliflora. It 



vp''^^ M I ^g^r^'^ is remarkable on account of its rapid 

 ^«^;^^]^^||^^/' ,:/ growth, as it becomes mature, and ex- 

 liibits the circular hole made by the 

 exit of the fly, within a i'ew days after 

 the bursting of the buds. It is spheri- 

 cal, oviform, or knobby, and either of 

 a yellowish white or yellowish green 

 colour, partly rosy, and covered with 

 short scattered hairs ; at its base it 

 rests on the large exterior bud-scales ; 

 the interior scales, which easily fall 

 oflT, are dispersed about its upper part. 

 It consists of a juicy, thin -walled 

 marenchyma, and contains from one to five cells, which are 

 conspicuous on the outside, appearing like bumps, and are 

 often distinctly divided by furrows; in the interior a some- 

 what perpendicularly-placed marenchyma forms the division 

 of the cells. The cells are large in comparison to the size of 

 the insect, generally oviform, and for the most part placed 

 upright on their longitudinal axis. The galls are often so 

 small that. the buds which contain them can only be recog- 

 nised through the bud-scales which are less regularly placed 

 and are more open. Each gall-fly, when escaping, makes a 

 circular hole in the substance of the gall, but it is done in 

 such a manner that the piece cut out is left adhering at one 

 point. Soon after the escape of the fly the gall shrivels up 

 to such a degree that we only meet with a dry crippled bud 

 in its place. Dr. Giraud states, in his ' Signalements,' &c., 

 that he found many galls on April 20th already pierced, and 

 yet he obtained a nuujber of flies up to April 23rd. On 

 the 17th of April, last year, 1 found these galls on the 



Gall of 

 Spathegaster aprilinus. 



