1911 ENTOMOLOGICAL SOCIETY. 65 



gall of B. rugosa, Froggatt, is emerald green, cylindrical, constricted at tlie base, 

 stout with thick, soft walls, the apex truncate ; length, four lines ; breadth one line. 

 In several species these male galls grow upon the female gall ; B. munita, Shrader, 

 has the males separate and springing from the horns; in B. phratrata, Shr., B. 

 thomtoni, Frogg., and B. nux, they are congregated together in a cup-like growth. 

 This growth expands like a flower, and is, I am afraid, rather inaptly described by 

 Shrader as a cockscomb, and as a mushroom-like growth by Froggatt. There is 

 generally only one cup-growth attached to a female gall, but B. nux, as a rule, ha? 

 two and often three. They are attached at one side of the summit of the female 

 gall, which they often exceed several times in size. 



The Female Galls exhibit a great variety of forms, which are the easiest means 

 of distinguishing the different species, varying in size from one-half to six or seven 

 inches in length. In the shape there is as great a variety as in the size; many of 

 them resemble cone-like fruits, others nuts and fruits, whilst the lateral growths of 

 B. duplex are not unlike leaves. Occasionally growing on stalks, they more often 

 s?it close upon either the twigs, branches, or leaves, from which they spring. 



The Formation of Galls. — The number of various gall-making insects which 

 have the remarkable power of diverting the forces of nature, as represented in the 

 growth of a plant, to their own advantage, has given rise to a deal of speculation 

 and experiment to discover the inherent element of property possessed by the insect 

 by means of which it operates. Up to the present we can go no further than to say 

 that the galls are due to an irritation set up by the insect, yet each individual species 

 must have some peculiar projierties or how would we find such widely differing 

 results when in their initial stages the producers are as alike as the two proverbial 

 peas? Mr. Tepper asserts that the larvae always select an embryo-bud, and by the 

 context he evidently wishes an undeveloped but true bud to be understood. This, 

 is, however, not the case; it may hold good in some instances, but certainly not in 

 all. Whether upon stem or leaves the gall-growth originates from the cambium 

 ring; the developmental activity of the cells is released by the insect, and a shoot 

 forms over the growth of which the animal maintains direction. This is proved 

 by the cessation of growth when the coccus, in a young stage, is killed by parasites. 



The rudimentary gall, according to Dr. Alder, draws its nourishment from the 

 surrounding tissue; later on, however, processes are driven into the gall from the 

 spiral vessels of the cambium ring, which form a new element to assist in its de- 

 velopment, and it thus becomes an independent structure, having individual powers 

 which regulate its shape, position, etc. These remarks, whilst referring to galls 

 formed by wasps, apply equally to coccid galls." 



Secretions. 



One of the main characteristics of the Coccida?. is their habits of secretion. 

 Like the Aphids the insects secrete a sweetish substance known as honeydew, which is 

 the sole food of several species of fungi and the chief food of many species of Ants. 

 This fluid is excreted entirely by the females by a special organ, a cylindrical tube 

 exserted from the genital orifice after the manner of the telescope. Honeydew is 

 attractive to many other nectar feeding insects besides the ants, such as the Hive 

 Bee and Bumble Bee and many species of Wasps. 



A species known as Physol'ermes ahietis found at Guelph, gives off a wax-like 

 secretion which is collected and used by the Hive Bees in constructing their 

 cells. This species is very abundant on Norway Spruce, and although causing con- 

 siderable harm in the tree is very beneficial to the bee in supplying material for the 

 foundation of its cells. 



