KEY TO AMERICAN INSECT GALLS 13 



National Museum Proceedings 53:357-80, 1917) indicates that a 

 change must be made in several of the best known Cynipid genera, 

 namely, that Cynips of authors not Linnaeus is Adleria Rohw. and 

 Fag., Dryophanta Forst. is Cynips Linnaeus and that Rhodites 

 Hartig and Diplolepis Goeff. are synonyms. In view of the fact 

 that the above genera are so well known and have been so generally 

 used in literature, it was considered best to continue these names 

 in this key, since it would be decidedly more convenient for those 

 wishing to refer to earlier accounts. 



Certain insect galls are commercially valuable and on looking 

 into the matter one may be surprised at the important place they 

 hold in trade. It is well known that some oak galls have long been 

 used in the manufacture of ink, particularly the more permanent 

 writing fluids. The amost important gall for this purpose is the 

 Eurasian Cynips gaUae-tinctoriae, variously known as the 

 Aleppo gall, Turkey gall, Levant gall, gall nut, gall of commerce and 

 ink marble. This gall contains 65 per cent of tannic acid and is 

 mostly used for dyeing wool and skins. The Knoppern or acorn gall, 

 produced by Cynips quercus-calycis contains 50 per cent 

 tannic acid and is next in importance to the Aleppo gall. There is a 

 Chinese sumac gall produced by a species of Pemphigus, closely allied 

 to the American P. r h o i s, that is imported in considerable quanti- 

 ties because of its high tannin content, a characteristic also of our 

 native gall. The air dried Chinese gall contains over 60 per cent 

 tannic acid and our native sumac gall about 8 per cent less. It is 

 probable that a number of American oak galls in particular could be 

 utilized to advantage. Insect galls are used in medicine on account 

 of their astringent properties and a few have served as articles of 

 food, notably that of a species of Aylax on Salvia pomifera 

 which forms an article of commerce in the Near East and a somewhat 

 common catmint gall, Aylax glechomae. Both are said to 

 have an agreeable taste and the sweet odor of the host plant. The 

 producer of the latter has become well established in this country. 

 Other galls are known to be edible and it is possible that they could 

 be turned to good account when the insects are unusually abundant. 

 There is a record of a black oak gall somewhat resembling wheat 

 and provisionally referred to the genus Callirhytis being so abun- 

 dant in Missouri and Arkansas some years ago that it was fed to 

 various domestic animals with excellent results. One gall, that of 

 Cynips theophrastea, was used by Greeks as a fuel in 

 lamps. For an excellent historical account of the use of insect 



