6 Bulletin 2: Springfield Museum. 



Family, Trypetidae. 

 These flies are most of them nearly as large as a house-fly. There are 

 few that produce galls. The galls are comparatively complex. 



Family, Cecidomyidae, Gall-gnats. 



These are small two-winged flies which are seldom noticed. The eggs are 

 laid on a surface of the plant. The larvae either feed from the surface, 

 making an open gall, or gnaw into the tissues of the plant, making a 

 closed gall which opens on maturity at the place where the larva entered, 

 altho during the growth no opening may be evident. The larvae can 

 generally be identified by the color, yellow, orange, or reddish, and by the 

 structure of an organ near the anterior end, which has been designated the 

 "breast-plate" or "breast-bone." These gall-makers are numerous both 

 in species and individuals. Their galls are sometimes quite complex 

 in structure. 



Order, LEPIDOPTERA. 

 Families, Tineidae, Elachistidae, Gelechiidae, Tortricidae. 



The adults are very small moths. There are very few gall makers 

 among them. The eggs are laid on the surface of the plant, the larvae 

 enter the tissues and either leave an opening, as in the gall of Ecdytolopha 

 insiticiana on the locust, or just before pupation gnaw almost through the 

 wall, leaving a place for the emergence of the adult, which, of course, 

 having no organs for boring or biting, could not otherwise escape. 



Order, HYMENOPTERA. 

 Family, Tenthredinidae, Saw-flies. 

 The members of this and the following family are four-winged insects. 

 The adult tenthredinid is distinguished by the structure of the ovipositor, 

 which consist of several toothed blades, by which the insect cuts or saws 

 into the plant tissue, and there deposits the eggs. AVhether a gall-maker 

 deposits also some irritating liquid which causes the gall is a much dis- 

 cussed question. However that may be, it is true that the only cases so 

 far directly observed in which a gall is formed before or without the hatch- 

 ing of the egg have been in this family, among the Nematinae. The larvae 

 somewhat resemble caterpillars. Several species make galls on willows. 



Family, Cynipidae, Gall-wasps. 

 In the adult the abdomen is usually compressed. The ovipositor is 

 long and slender, and can well bury the egg within the plant-tissue, leaving 

 no mark. The larvae pupate in the closed gall, and the insects when 

 mature cut their way out of it. Alternation of generations is one of the 

 most interest ins: features in the life of these highest of gall-makers. The 

 galls are, without exception, complex in structure, with several distinct 

 divisions of the walls, and many interesting adaptations for the protection 

 of the inmate. 



