27 



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 manufacturinof and utiJizinof 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 a.m. 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 recentty called 

 attention to peculiarities in the structure of the head and mouth parts which set 

 this group quite aparfc 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 maxillae. 



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 Stenopteridse and 

 Coleoptratidae, 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 Phlaeothrips 

 are found to be more nearly symmetrical. 



As an interesting fact, though in no way related to the main purpose of this 

 communication, I may mention that the solitary mandible of Limothrips and 

 Melanothrips is perforate, like the jaws of larval Chrysopa, of Dytiscidae, and of 

 Myrmeleon. In specimens of Coleoptratidse examined, both labial and maxillary 

 palpi are composed of three segments. 



I^ote. — Since my return to Lexington from the meeting of the American Asso- 

 ciation I have secured a couple of very young Phlaeothrips. My examination of 

 these is not completed, but I 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 



