58 REPORT OF No. 19 



value in classification. The galls produced vary in form, but are always 

 open or provided with an opening through which the mites pass in and out. 

 They are generally lined with minute hairs or granules, and are quite simple 

 in structure. Reproduction takes place within the gall. 



Coleoptera. 



Family, Buprestidae. Metallic Wood Borers. 



This is a family of the beetles containing insects whose larva bore in 

 wood of trees and shrubs. A few produce galls, the most important one 

 being the Red-necked Agrilus producing galls upon the Raspberry and 

 Blackberry canes. 



Lepidoptera. 



Super-family, Tineidae. Leaf miners and clothes moths. 



This family is very large and the larvae are mostly plant feeders. The 

 adults are minute moths with narrow wings bordered with wide fringes. 

 The family contains but few gall-makers. 



HeTniptera. 



Family, Aphididae. Aphids or plant lice. 



These are small, soft bodied insects which suck up the juices of plants 

 and which often produce galls. There are winged and wingless forms, the 

 wingless forms reproducing parthenogenetically. The galls produced vary 

 in form from mere leaf curls to forms of most curious appearance but of 

 quite simple structure. They are all open or furnished with an opening, 

 and large numbers of the aphids can be found if the gall is opened. 



Family Psyllidae. Jumping plant Jice. 

 The members of this family resemble the preceding to a great extent, 

 but they are not so numerous. The hind legs are formed for jumping. 



Diptera. 



Family, Cocidomyiidae. Gall gnats. 



These insects in the adult stage are rarely seen. They are very delicate, 

 small, two-winged flies and with few veins in the wings -and with sucking 

 mouth parts. The eggs are laid upon the leaf surface and the larva either 

 fepds there, making an open gall, or makes an incision in the leaf and enters, 

 forming a closed gall, which splits open at maturity at the point where the 

 larva entered. The larvae can generally be readily identified by their color, 

 which is orange, red or pink, and by the development between the second 

 and third segments of the body of a, peculiar horny projection called the 

 breast-plate, the use of which is not definitely known. 



Sub-family, Trypetinae. 

 These flies are much larger than the preceding, but few of them produce 

 galls. Two species, Trypeta polita and Trypeta solidaginis, produce galls 

 upon the goldenrod. The adults are pretty flies with banded wings. 



Hymenoptera. 



Family, Tenthredinidae. 



In this family the Nematinae produce galls. The head and thorax art 

 wide. The base of the abdomen is broadly joined to the thorax, and the 

 abdomen of the females is furnished with a pair of saws. The larvae have 

 from twelve to sixteen prolegs. These insects have been very thoroughly 

 taken up by Norton in his monograpu on Nematinae. A large number make 

 galls on Willows. 



