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shade trees of New York by P. cecropia was recorded, and the suggestion made 
that this and other species might be turned to account, if any means could be 
devised for manufacturing and utilizing their silk. As a stimulus to this indus- 
try, Mr. Graef generously offered a prize of fifty dollars for the best essay and 
model of apparatus for carrying this suggestion into effect. 
SECOND DAY’S SESSIONS. 
The Club met on Thursday at 8 am. Dr. C. M. Weed read an interesting 
paper upon the clover-stem borer, Languria mozardi. Fifteen species of plants 
were reported upon which the larva had been found feeding. This paper was 
discussed by Profs. Cook, Alwood, Osborn and others. 
Prof. Alwood spoke of tobacco insects, of which he was making a special 
study. He had observed a stem borer which was very injurious. 
Dr. Weed had learned of a tobacco root-louse in Southern Ohio. 
Prof. Garman spoke of the mouth parts of several species of some families 
of Thysanoptera, and stated that some recent studies had shown him that the 
figures published did not agree with his material. He then read the following 
paper, entitled “An Asymmetry of the Head and Mouth Parts of Thysanoptera.” 
In a brief paper in the Bulletin of the Essex Institute I have recently called 
attention to peculiarities in the structure of the head and mouth parts which set 
this group quite apart from other orders of Hexapoda. [This has no reference to 
affinities upon which, I believe, we are not prepared to pronounce until this and 
several other groups have been more completely studied.] In that paper it was 
. claimed that the endocranium of the species examined was not symmetrical, being 
deficient on the right side; that the labrum was one-sided; that there was a 
developed mandible on the left side, with, at most, a rudiment on the right ; and 
that the mandibles of authors were probably lobes of the maxille. 
At the time the paper was written I had not examined sufficient material to 
enable me to say whether the features pointed out were limited to certain species 
or were common to all members of the group. Since then many additional forms 
have been examined, all, however, belonging to the families Stenopteride and 
Coleoptratidie, and in no case has there been found a departure in essentials from 
the structure of the head and mouth parts as they were described in the paper 
referred to. It is probably safe to assume, therefore, that the asymmetry noted 
is characteristic of these two families at least. 
Of the group Tubulifera no representatives have been studied, I shall not 
be surprised, since this is the lowest of the suborders, if examples of Phleothrips 
are found to be more nearly symmetrical. 
As an interesting fact, though in no way related to the main purpose of this 
commuuication, I may mention that the solitary mandible of Limothrips and 
Melanothrips is perforate, like the jaws of larval Chrysopa, of Dytiscide, and of 
Myrmeleon. In specimens of Coleoptratidee examined, both labial and maxillary 
palpi are composed of three segments. 
Note.—Since my return to Lexington from the meeting of the American Asso- 
eiation I have secured a couple of very young Phlothrips. My examination of 
these is not completed, but 1 have succeeded in demonstrating the single jaw on 
the left side. The parts are greatly elongated, and remind one of the same 
organs in Hemiptera. The styliform parts are especially long, extending, when 
