420 The Ohio Naturalist. [Vol. Ill, No. 7, 



globular gall. At this late stage the only evidence that we have 

 of its bud origin is its location at the node of the main stem. 

 The transition from bud to gall occurs \er\ earh^, before there is 

 any differentiation of the parenchyma tissue ; examination of the 

 structure of the gall fails to show any stem characters but does 

 show the Cynipidous gall character described in Part I of this 

 series. 



(3) The third type of the bud gall is illustrated in .hidriais 

 semvmtor Harris (Figs. 35, a, b, and 36, a, b.) Ashmead''- refers 

 to this as a flower gall. It is not difficult to demonstate that this 

 gall is a true, compound bud gall, but whether it is a flower or 

 leaf gall is not so easily determined. The strongest evidence of 

 its bud character is its location at the node of the stem and the 

 presence of the leaf scales at its base. The writer gathered and 

 dissected a large number of galls of various ages and is confident 

 that this is a true compound bud gall. In Figure 35 a, we have 

 a short twig with three buds, one of which was attacked by the 

 insect ; the other two buds remained unaffected Around the 

 base of the gall are four well-defined bud scales. In Figure 35 

 b, two buds were affected ; one of these has been removed show- 

 ing the scar where it was attached and also exposing the back 

 side of the compound gall formed from the other bud. A great 

 man}' galls of various ages were dis.sected ; the j-ounger ones 

 showing the bud scales and the older ones showing the well- 

 defined scars by which it was easy to trace the number of buds 

 affected. Careful observations were made in hopes of finding a 

 gall which would show whether this w^asa leaf or flower bud, but 

 without success. However, from a careful microscropic examin- 

 ation of a number of galls I am inclined to consider it a leaf bud, 

 in which each leaf becomes a single gall of the large cluster and 

 in which the incipient stem remains short. Tiie microscopic 

 examination of the single galls ( Fig. 36, a, b) shows that each 

 gall contains at least one (and usually only one) fibro-vascular 

 bundle which in most caises is very much atrophied and in some 

 cases so much reduced as to be very indistinct. The writer 

 considers the fibro-vascular bundle as the mid-rib of the modified 

 leaf and the cottony part of the gall as the mesophyll part of the 

 leaf. This gall does not show the four zones which are charac- 

 teri.stic of the cynipodous galls as pronounced as other galls 

 which we have examined, but this point will l^e discussed in a 

 later paper. 



(4) The fourth type of gall is illustrated by a cecidomyid gall 

 (Fig 37) found upon Acer negundo in which the bases of the 

 petioles of a number of leaves from the same bud are enlarged. 



*Ashmead. Win. 11.: "On the Cynipidous (ialls of l<'k)ri(l;i, with descriptions of new 

 species and synopses of the described species of ^orth .•America." Trans. .•Vnier. Hnt. Sec. 



Vol. .\IV, pp. I2,S-12.S. 



