Insect Galls. 5 



Hemiptera (Families, Aphididae, Psyllidae). 

 Coleoptera (Family, Cerambycidae) . 



Diptera (Families, Agromyzidae, Trypetidae, Cecldomyidae). 

 Lepidoptera (Families, Tineidae,Elachistidae,Gelechiidae, Tortricidae ) 

 Hymmoplera, (Families, Tenthredinidae, Cynipidae). 

 (For a more complete list of the species under each family mentioned 

 above see the list serving as index of the gall-insects near the end of this 

 Bulletin.) 



In general the more highly organized insect produces the more complex 

 gall. There may be apparent exceptions to this rule, as in the case of the 

 bark louse, Adelges abietis, producing a gall at the base of needles of the 

 spruce which is very similar to one produced on the needles of the pitch 

 pine by a two-winged fly, Diplosis pini-rigidae. 



Order, AC A R IN A. 

 Family, Eriophyidas, Gall-mites. 

 These mites are of minute size, and are to be found among the hairs or 

 grains with which the concave surface of the gall is lined. There are 

 several generations during the summer, the newly hatched mites moving 

 out over the plant and producing new galls. The adults hibernate under 

 the scales of buds or in crevices in the bark. A few species are found in 

 such numbers on the leaves of cultivated fruit trees or shrubs as to cause 

 much damage, the aborted leaves not being able to provide sufficient food 

 for the development of the fruit. The galls are usually very simple in 

 structure, and always have an opening by which the maker can pass out 



Order, HEMIPTERA. 

 Family, Aphididae, Plant-lice. 

 These insects are soft-bodied, with sucking mouth-parts There are 

 winged and wingless forms, the latter reproducing parthenogenetically. 

 There are several generations in a season. The galls are usually quite 

 simple in structure and contain many insects. There is an opening for 

 their egress, altho in a few cases this remains closed until the gall matures 

 and dries slightly. 



Family, Psyllidae. 

 These are much like the aphids, but have hind legs fitted for jumping. 

 The galls are similar in general structure, altho possibly a little more 

 complex. 



Order, COLEOPTERA. 

 Family, Cerambycidae, Longicorn beetles. 

 Most cerambycid larvae are borers in the wood of ti-ees and shrubs, a 

 few in herbaceous plants, but the larvae of a few species produce galls. 



Order, DIPTERA. 

 Family, Agromyzidae . 

 The production of galls b} r the larvae of agromyzids is very exceptional ; 

 most of these larvae mine in the leaves or stems of plants. 



