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HARDWICKE'S SCIENCE-GOSSIP. 



tologist to the Geological Survey of Ireland. This 

 work appeared in four five-shilling parts, which 

 brought the descriptions to the close of the Palaeo- 

 zoic system. These parts are now republished in 

 one handsome volume. The illustrations are 

 numerous and excellent, and the letterpress 

 delineations clear, accurate, and fully instructive. 

 We cordially recommend this work to all young 

 geologists. 



NOTES AND QUERIES. 



Teeth of a Fly. — If your correspondent " T. J. 

 B." had either written to or called upon R. & J. 

 Beck, from whom the slide " Teeth of a Fly " was 

 purchased, it would have saved both him and his 

 friends from the mistake into which they have fallen 

 by imagining that the sliced ends of the spiral tubes 

 at the end of the fly's tongue are sold as " the 

 Teeth of a Fly." At the base of these spiral tubes 

 (as any elementary work on the anatomy of the fly 

 will explain), there are several horny appendages 

 with sharp, knife-like edges, which are no doubt 

 well shown in the specimen to which he refers, and 

 are known as the teeth. If "T. J. B." will care- 

 fully re-examine the slide, he will see, and be no 

 doubt able to convince his friends, that the purchaser 

 of this object has neither been "defrauded" nor had 

 "palmed off" upon him any preparation under 

 a false pretence. It is a great pity that persons do 

 not make rather more inquiry before committing 

 themselves in print to expressions likely to subject 

 them to legal proceedings.— B. $• J. Beck. 



Teeth of a Fly.— I beg to inform " T. J. B.," in 

 answer to his query in last month's Science- 

 Gossip, that flies have teeth, and that if he looks 

 more carefully at the slide of his F.R.M.S. friend, 

 he will probably see them as bideutate rods, situated 

 between the bases of the so-called pseudo-tracheae, 

 which are really suctorial channels. In the Blow- 

 fly there are three rows of these teeth, and, conse- 

 quently, thirty in each lobe of the lips, or sixty in 

 the whole organ. If " T. J. B." will soak the pro- 

 boscis of a blow-fly in liquor potassae for a week, 

 cut off the lips, and then tease them out with fine 

 needles under the dissecting microscope, he will be 

 able to expose the teeth, and satisfy himself as to 

 the facts. The ily is a suctorial insect, but the 

 teeth are used to triturate the sugar or other food, 

 which then being liquefied by the saliva is sucked up 

 through the suctorial channels and the proboscis. 

 If " T. J. B." will look at page 332, vol. i. of the 

 Monthly Microscopical Journal, he will fiud a 

 capital drawing of these teeth by Mr. Suffolk, from 

 a mountrd preparation I made and sent to him. 

 He can also consult Mr. Lowne's excellent work on 

 " The Anatomy of the Blow-fly." — Major Lang. 



The Teeth of Flies.— The communication of 

 your correspondent "T. J. B.," who, in the last 

 number of Science-Gossip expressed his anxiety 

 to be informed whether flies have teeth, set me to 

 look up authorities on the subject ; and with your 

 permission I will give the result of my researches. 

 Mr. Suffolk contributes an illustrated paper " On 

 the Proboscis of the Blow-fly," to the Monthly 

 Microscopical Journal for June, 18G9, in which he 

 says -.—"The pseudo-tracheae above and below the 

 oral aperture are arranged in four groups, each 



connected with a larger tube, these four main tubes 

 emptying themselves into the oral aperture ; the ten 

 central tubes on each side of the mouth open directly 

 aud independently, having disposed between them 

 long forked appendages ; the teeth, arranged in three 

 rows, the back row of which perhaps are hardly to 

 be considered as proper teeth, as they are attached 

 rather closely to the membrane of the lips. The 

 office of these teeth is undoubtedly that of cutting 

 instruments or scrapers. I have examined caraway 

 comfits after flies have fed upon them, and found 

 them covered with parallel scratches, the distance 

 of which, when measured with the micrometer, 

 corresponded exactly with that between the teeth." 

 Respecting the teeth of Musca domestica, Captain 

 Lang remarks, "That there appears to be only one 

 row, each tooth considerably broader than in Musca 

 vomitoria and tridentate; and on either side of these 

 principal teeth may be seen a very delicate one, 

 so that there are the same number as in the blow- 

 fly, though differentlyarranged." Again, Mr. Lowne, 

 in his monograph on " The Anatomy and Physiology 

 of the Blow-fly" (pp. 47, 48), writes :— " The 

 anterior surface of the lobes (of the proboscis) is 

 channelled by a series of canals, kept open by in- 

 complete rings, called false tracheae, which open 

 internally into the cavity between the lobes, and so 

 into the mouth : these form a fine strainer, through 

 which the insect is enabled to filter the fluids from 

 the solid portion of the substances on which it 

 feeds. The lobes are, however, capable of further 

 separation, exposing the triangular opening, which 

 is surrounded by from fifty to sixty bidentate rods or 

 teeth, which are usually concealed between the pos- 

 terior portions of the lobes, but are used, when 

 exposed, for grinding hard substances, such as sugar ; 

 so assisting the salivary secretion to dissolve them." 

 Possessing a slide similar to the one described by 

 U T. J. B.," labelled by Messrs. Smith & Beck, 

 " Teeth of a Fly," I have again examined it under 

 a one-third objective, with B eye-piece ; and I 

 must confess my inability to discover the teeth as 

 figured by Mr. Suffolk. The false tracheae have a 

 rasping surface, apparently quite capable of making 

 marks upon sugar ; and it has occurred to me (subject 

 to correction by more experienced investigators) 

 that the preparer of the object in question has 

 mistaken the false tracheae for teeth.— John Ford, 

 Wolverhampton . 



Mistletoe on Trees.— In reply to " R. S. T.'s " 

 question, in the February number of Science- 

 Gossip, I am able to inform him that we have a 

 fine bunch of mistletoe growing on au acacia in our 

 garden in Sussex. — E. S. G. 



Mistletoe. — I have known mistletoe to grow on 

 a pink May-tree in Surrey, in Hampton Wick : 

 could any of your readers tell me if it is generally 

 known ?—J. W. Mee. 



Mistletoe. — As supplemental to the trees men- 

 tioned by your correspondent " R. S. T." as sup- 

 porting mistletoe, allow me to direct his attention to 

 the article Viscum, in " The Treasury of Botany " : 

 we there read that "next in frequency to the 

 apple, the mistletoe prefers the poplar; though 

 it is not found on the Lombardy poplars; haw- 

 thorns, limes, maples, and the mountain ash are 

 all favourite habitats for the plant. It has been 

 found on the cedar of Lebanon and on the 

 larch." In the Kew museum there are British- 

 grown specimens upon maple, hawthorn, and hazel, 

 and upou Sorbus sp. and Acer opulifolium from 

 Mentone. — John R. Jackson. 



