SCIENCE- GOSSIP. 



187 



form on the part of the slide covered by the tube, 

 and, if satisfactory, can be mounted in the usual 

 way. Camphor, arsenic, and many others will 

 suggest themselves as suitable for this method. 

 These three methods practically cover the whole 

 ground of preparing crystals for the microscope, 

 and, if mounted in a suitable medium and pre- 

 served from undue heat and light, these slides will 

 be permanent ; any change which may take place 

 in the forms of the crystals may be put down to 

 the solvent action of an unsuitable medium. 



MEETINGS OF MICROSCOPICAL SOCIETIES. 



Royal Microscopical Society. — 20 Hanover 



Square, November 20th, 8 p.m. 

 QuBKBTT Microscopical Club. — 20 Hanover 

 Square, November 1st, 7 p.m. ; November 15th, 

 8 p.m. 

 Manchester Microscopical Society. — Mount- 

 ing Section, Grand Hotel, November 21st, 7 p.m. 

 " Life History of Fucus Vesiculosus " (Mr. 

 Cottam) ; and Practical Demonstration of the 

 Various Methods of Microscopic Illumination. 

 [For further articles in this number on Micro- 

 scopic subjects, see pp. 173 and 189.] 



EXTRACTS FROM POSTAL MICROSCOPICAL 

 SOCIETY'S NOTEBOOKS. 



[Beyond necessary editorial revision these ex- 

 tracts are printed as written by tlie various 

 members. — Ed. Microscopy, S.-G.] 



Insect Anatomy. 



{Continued from i>iuj- ISP.) 



Proboscis of BiittcTfly. — The tongue, or proboscis, 

 is a cartilaginous substance, and owes its great 

 flexibility to being formed in rings, which give it a 

 finely-engraved appearance under the microscope. 

 It is formed of two pieces that can be separated 

 through its whole length, and each being grooved 

 on the inner side they fit together perfectly air- 

 tight ; this is effected by an infinite number of 

 fillets resembling the laminae of a feather which 

 interlace and adhere to each other. Between this 

 groove and tlie outer skin is a space occupied by 

 tracheae or breathing tubes. The proboscis is 

 always carried coiled, but can be uncoiled in a 

 moment. It is perfectly suited to the work of 



cVj'ltinjOUs v^aUs, 

 lutr)trj /' '1 



Pig. 1. Section thuougii Proboscis of Cabb.^cie 

 Bl'tteufi.y. 



penetrating to the honey of flowers. We know how 

 butterflies close their wings as they alight on a 

 flower, when the insect makes a powerful ex- 

 piratory effort by which the air is expelled from all 

 tracheae. At tlie moment of applying its proboscis 

 to the food it makes an inspiratory eft'ort by which 

 the tube of the proboscis is dilated and the food 



ascends at the same moment to fill the vacuum 

 produced, thus passing to mouth and stomach, 

 being further assisted thereto by the muscles of 

 the proboscis. — \_Mrs.~\ W. Major. 



The function ascribed above to the tracheae is 

 a novel one, and it is difficult to understand how a 

 vacuum can be produced in the oesophagus and its 

 connections by driving the air out of them, even if 

 it were possible. In insects the mouth can only 

 be considered as connected with respiration in the 

 most indirect manner, if at all ; for, although in 

 certain acari the air -tubes open at the base of the 

 mouth, there seems to be nothing analogous in in- 

 sects. Respiration in insects is effected by means 

 of two large canals, called " tracheae," running 

 along the sides of the body underneath the outer 

 surface, which communicate with the air by 

 short tubes called spiracles situate along the sides. 

 I ta.ke it that tliese tubes can never be exhausted 



proboscis. 





S^oiT)QeK. 



StomacK. 



— bile "twbee. 



)-/ iD^'s^io'. 



edu 



'D- 



Fig. 2. Ai.i.MEXTAiiv Canal of Pieiiis brassica. 



of the air they contain, seeing the walls are sup- 

 ported by spirally convoluted fibres, which impart 

 great strength and prevent collapse ; and that the 

 air is changed within them, according to the 

 necessity of the creature, by the closing or opening 

 of the spiracles and the continuous rhythmic 

 movement of the body. It may be well to say a 

 few words with respect to the means by which in 

 the Proboscidea the food is drawn up into the 

 stomach. The Hymenoptera. Lepidoptera. and 

 Diptera are provided with a bladder-shaped dis- 

 tension of the oesophagus which would appear to 

 be a modification of the crop, and is called a 

 '■ sucking stomach." This is not a receptacle for 

 food, but by its distension and the consequent 

 rarefaction of the air contained therein it promotes 

 suction of the same and facilitates the rising of 

 fluids in the proboscis and the oesophagus, and it 

 is by this means these insects rifle the flowers of 

 their contents. — E. Bostock. 



I happen to have some transverse sections of the 

 so-called tongue of the Cabbage Butterfly. I have 

 made a rough di-awing (fig. 1) of one. This shows 

 the organ to be composed of the two maxillae, the 

 walls of which enclose a tracheal vessel, muscles. 



