20. 
21. 
22. 
23. 
24, 
25. 
26. 
ale 
Prolegs absent; last segment often heavily armed 
Coleoptera, Tenebrionidae 
Prolegs absent; larvae curved, grublike; in willow, pop- 
larvandwpalmettoy. 2.2... Coleoptera, Curculionidae 
Prolegs present; last segment not heavily armed 
Lepidoptera, Hepialidae, Aegeriidae 
Larvae depressed, flat-headed or pestle-shaped 
Coleoptera, Buprestidae 
Larvae curved, grublike ............ Coleoptera, Curculionidae 
Larvae slender; thoracic segments not noticeably en- 
larged; cause pitch flecks in wood, birch, ete. 
Diptera, Agromyzidae 
Larvae with prolegs; poplar, willow, alder, ash, persim- 
MOM Aare Neer os Lepidoptera, Hepialidae, Aegeriidae 
Larvae without prolegs 
Inghardwoodsies<5 2405.2. Coleoptera, Cerambycidae 
In conifers; associated with pitch mass 
Coleoptera, Curculionidae, Scolytidae 
EB. Galls § 
Galls of more or less open, exposed, simple structure, or, 
when enclosed, the insects maintain permanent open- 
ings, or the gall is dehiscent to permit the escape of 
rarely, several insects to a cavity; occasionally a per- 
manent opening is maintained by the feeding larva. 
Mites present having 2 pairs of legs; galls of various 
shapes but always provided with an opening to the 
exterior and lined on the inside with hairy or fuzzy 
POMC INSGe ee ee he Se EN. ci Brag ee A cnn ee hee Acarina 
Galls otherwise ......... Satie Bir ane Siow ath de leanne es 7 | 
Insects=not.fitted. for JUMPING ...8..60.8 ban 
Insects with hind legs developed for jumping 
Homoptera, Psyllidae 
Leaf galls on hardwoods, chiefly elm, poplar, hickory, 
ash, sumac, and witch-hazel 
Homoptera, Aphididae 
Conelike galls on tips of spruce twigs 
Homoptera, Chermidae 
Pitlike galls on twigs of hard pines 
Homoptera, Margarodidae 
Pitlike galls on twigs of white oak 
Homoptera, Asterolecanidae 
Galls inhabited by larvae with a well-developed head 
capsule ..... NaC e ee hae eee ae eee a ae ne 
Larvae without well-developed head capsule, maggot- 
like; white to yellowish or reddish in color: 
24 
27 
25 
26 
28 
Salt seems impossible to devise a key that will separate all the varied 
types of galls into family or order groups. On the other hand, many groups 
are fairly true to type, and if considered with the larvae or other stages of 
the insect inhabiting them, you can make a fairly workable distinction. 
30 
