284 



THE AMERICAN ENTOMOLOGIST. 



PROCEEDINGS OP THE SEVENTH ANNUAL MEET- 

 ING OP THE ENTOMOLOGICAL CLUB 

 OP THE A. A. A. S. 



( Con, luded from /. 274 . ,i 



At the meeting Tuesday evening, 24th 

 August, in Parlor 15 of the Hotel Ven- 

 dome, Mr. H. F. Bassett, of Waterbury, 

 Conn., made a communication upon the 

 structure and development of some Hy- 

 menopterous galls, detailing the course of 

 development of the galls of Cynips opera- 

 tor on Qu. ilicifoUa. These galls, as well 

 as those of Cynips scminator on Qn. alba, 

 are developed from buds. Referring to a 

 discussion contained some time since in 

 the columns of " Nature," Mr. Bassett 

 said that while some galls are undoubtedly 

 abnormally developed buds, others are not 

 buds at all. The young acorns of Qu. ilicifolia 

 which are infested by C. operator., develop 

 from their sides small pseudacorns in the 

 fall. These pseudacorns fall to the ground 

 about the first of September and remain 

 21 months before the perfect insects are 

 developed from them. These perfect in- 

 sects are all females. Their progeny in- 

 habit woolly galls, which develop males 

 and females in 90 days from the laying of 

 the eggs. 



Mr. Bassett regards the galls of Cynips 

 seminator and C. operator as aborted leaf 

 blades. The wool upon them is an exces- 

 sive development of the pubescence of 

 the leaf. In C. operator the egg is laid by 

 the parent insect in the midrib of the leaf; 

 in C. seminator it is deposited in the 

 petiole. 



These galls are made to grow by the de- 

 position of poison in the puncture made 

 by the parent insect when depositing her 

 eggs. 



The cynipidous galls are divided into two 

 classes, viz : those which are produced in 

 fall or winter or which remain undeveloped 

 more than one season, and those which 

 are produced and which develop in the 

 spring. The galls of the former class pro- 

 duce only female imagos, while those of 

 the second class produce males and fe- 

 males, the males appearing earlier. 



Dr. Hagen said he had arranged three 

 boxes at the Museum of Comparative Zo- 

 ology, in Cambridge, to illustrate Adler's 

 discovery of the dimorphism of Cynipidse. 



Mr. Riley said that a distinction should 

 be drawn between galls produced entirely 

 by the irritating action of the contained 

 larva and those owing their origin entirely 

 to the deposition of poison by the parent 

 insect, and cited instances of galls pro- 

 duced in both ways. 



The discussion recurred to the nature 

 and source of the sweet exudation found 

 upon the surface of galls on Qu. radiata 

 visited by the honey ants {Myrniecocystus 

 jne.xicanus). Mr. Riley cited observations 

 and experiments which proved that the 

 more common honey-dew is a natural ex- 

 travasation of the plant, and should be dis- 

 tinguished from that produced by Plant- 

 lice and Bark-lice. Dr. Hagen said he 

 did not understand how a sweet excretion 

 could be exuded from galls, which have an 

 acrid nature. Mr. E. P. Austin remarked 

 that the chemical composition of sugar 

 and woody fibre are the same, and that 

 sugar could be produced by conversion 

 from woody fibre in the plant. Dr. J. L. 

 LeConte said that he understood tannin 

 to be a conjugation of gallic acid and 

 sugar. Mr. B. P. Mann said that recent 

 observations, which he had found described 

 in a newspaper, had shown clearly the na- 

 ture of much of the moisture which ap- 

 pears occasionally at night in great abun- 

 dance on the leaves and other portions of 

 plants, and which is usually mistaken for 

 dew. This moisture differs from dew in 

 being produced under circumstances which 

 would not account for the formation of 

 dew, and in containing a perceptible quan- 

 tity of sugar. It is the ordinary watery 

 excretion from the surface of the plant, 

 which, under favorable conditions of the 

 atmosphere, collects in beads or in drops, 

 instead of evaporating as rapidly as it is 

 formed. 



Mr. Riley further said that many galls 

 exude saccharine matter, amongst others 

 those of certain /'^v/Z^-r^r^ on Hickory, one 

 of which he had named carxcB-^iimmosa on 



