1886.] 



MICROSCOPICAL JOURNAL. 



179 



used dry. I have tested it on all kinds of 

 work that could be done with such a high 

 power, and, as far as my experience goes, 

 I believe it to be superior in definition and 

 resolution to any high power that I have 

 ever examined. The picture given of 

 bacteria and micro-organisms is all that 

 could be desired. 



Pierce Tyrrell. 



MICROSCOPICAL SOCIETIES. 



Cleveland, Ohio. 



At the annual meeting of the Cleveland 

 Microscopical Society, all the officers were 

 re-elected for another year, viz: President, 

 C. M. Vorce, F. R. M. S. ; Vice-President, 

 Montague Rogers; Secretary, J. A. Wil- 

 son ; Treasurer, John Hoehn, Ph. G. 



o 



San Francisco, Cal. 



The regular semi-monthly meeting was 

 held Wednesday evening, June 9th ; Mr. 

 E. J. Wickson, presiding. 



A well-mounted slide of the beautiful 

 brine shrimp, A?'fe!ina Salina, was shown 

 under dark field illumination. This inter- 

 esting little crustacean is now found in 

 large numbers in the brine-pits of the salt- 

 works near Alameda. It is about one- 

 fourth of an inch in length, and each 

 segment of the thorax is provided with a 

 pair of branchial feet, the rhythmical 

 motion of which impart a very graceful 

 appearance to the animal when swim- 

 ming in the brine. 



The Secretary called attention to an 

 unusually fine mount of the head of the 

 male wasp obtained from Fred Enoch, 

 the well-known English preparer of ento- 

 mological objects. The slide was accom- 

 panied by a camera lucida sketch, show- 

 ing the upper and under sides, and desig- 

 nating the various organs. 



The remainder of the evening was 

 devoted to the examination of several 

 varieties of fruit pests, mainly insects be- 

 longing to the aphis and coccus families, 

 and their natural insect foes. The collec- 

 tion had been brought by Dr. Bates, who 

 narrated some interesting facts regarding 

 the same, and then called upon Mr. 

 Wickson for a further elucidation of the 

 subject. The latter stated that some ex- 

 periments were now being carried on at 

 the State University orchard with refer- 

 ence to keeping the destructive insects on 

 fruit trees in check, by fostering the prop- 

 agation of other insects which are the 

 natural foes of the former class. He cited 

 an instance of a plum tree which was 



apparently hopelessly overrun with the 

 plum aphis, but several varieties of the 

 well-known lady-bug, Cocchtella, soon 

 appeared in such numbers that the tree 

 became fairly red with them. As a con- 

 sequence, the aphides were losing the 

 ascendency, and the tree would no doubt 

 ultimately be rid of them. The larval 

 form of Coccinclla is even more useful 

 than the perfect insect, as a factor in the 

 destruction of aphides. Specimens of the 

 lace-winged fly (^Chrysopa perla) and of a 

 fly belonging to the genus Syrphus, to- 

 gether with their larval forms, were shown 

 under the microscope, and their peculiar- 

 ities of structure pointed out. The larva 

 of Syrphus is footless and blind, but 

 nevertheless creates great havoc among 

 the multitudes of destructive insects in^ 

 festing fruit trees. 



A. H. Breckenfeld, Rec. Seer. 



San Francisco, Cal. 



The regular semi-monthly meeting was 

 held on Wednesday evening, July 28th, 

 Dr. S. M. Mouser presiding. 



Pursuant to announcement, Mr. A. H. 

 Breckenfeld read a paper on ' Hydra, the 

 Fresh-water' Polype.' After referring to 

 the original discovery of this remarkable 

 little creature by that pioneer micro- 

 scopist, Antony van Leeuwenhoek, in 

 1703, allusion was made to the investiga- 

 tions of Trembley — by whom the animal 

 was practically re-discovered nearly forty 

 years later — and the great interest excited 

 thereby among the naturalists of Europe. 



Hydra consists essentially of an elon- 

 gated, nodular sac of protoplasmic sub- 

 stance, imbedded in which are found 

 large numbers of colored granules. At 

 the upper end of this sac is a simple 

 opening, the mouth, and just below this 

 is a circle of tentacles, usually from six 

 to ten in number. At the lower extremity 

 the body is furnished with a flattened, 

 suctorial disk, by means of which the 

 animal attaches itself to filaments of algae, 

 rootlets of duckweed, and similar objects, 

 while its slender, tendril-like tentacles 

 are slowly and gracefully waving about 

 in search of prey. The body and tenta- 

 cles, when fully extended, seldom meas- 

 ure over one-fourth or one-half of an 

 inch in length, except in the case of the 

 rare species H. fiisca, which sometimes 

 attains a length of several inches, owing 

 to the extraordinary development of the 

 tentacles, which in that species are many 

 times the length of the body. The ten- 

 tacles of Hydra are hollow, each being 

 traversed by a canal communicating 



