14 THE ENTOMOLOGIST 



smoothness within, and though not always perfectly separated 

 down to the base from its outer husk, yet quite clearly so in 

 some cases, as given in section at fig. 4, which shows the 

 blunt-pointed extremity a little drawn open, as for the exit 

 of the larval tenant. 



After exclusion has taken place the gall may be found as 

 at fig. 5, completely expanded, with the two involucral films 

 thrown back, showing the separation complete to the base, 

 and the sometime bluntly-pointed globose gall lying with its 

 extremities curved inward in the centre of its husk with its 

 cavity displayed, much like some cup-shaped flower in its 

 calyx. The galls vary much in size up to about three- 

 sixteenths of an inch in length, and in breadth in the longest 

 diameter. 



At the end of October the Cecidomyia uhnaricd, Bremi, 

 larvae were leaving the galls ; but except in cases of double 

 foruiation of the gall itself I never observed more than one 

 tenant in each. The operation of freeing itself was very 

 rapidly performed, in the only case I had the opportunity of 

 watching throughout, by the orange-coloured larva pressing 

 itself tail foremost down the funnel of the gall till it was 

 completely outside, then twisting itself head foremost it 

 curled and struggled for some time on the surface of the gall 

 (the long gall-hairs giving it power to keep hold), the only 

 long-continued position being when it placed itself upright 

 on one extremity, as if boring ; and on being transferred to 

 some earth it buried itself. 



By the 7th of December, although galls were still to be 

 found on the Spiraa leaves, all that were opened were 

 tenantless. 



Spring Grove, Isleworth, December 11, 1B77. 



DESCKIPTIONS OF OAK-GALLS. 

 Translated from Dr. G. L. Mayr's ' Die Mitteleuropaischen Eichengallen.' 



By Edward A. Fitch. 



(Continued from vol. x., p. 2'J9.j 



77. Cecidoinyia cerrls, Kollar. — The galls of this gall-gnat 

 may often be found in enormous numbers on the leaves of 

 Quercus cerris ; they generally appear about the middle of 

 June, sometimes still earlier. The gall appears on the upper 

 side of the leaf as a sujall conical leaf-swelling of about 



