2 66 



HARDWICKE'S SCIENCE-GOSSIP. 



quarter of an inch long. The thorax is of a drab or 

 greyish-brown colour, with a fairly well-defined stripe 

 of a slightly darker shade centrally situated. The 

 dorsal portion of the abdomen is slate, or lead colour ; 

 the ventral, a trifle lighter. Each segment of the 

 abdomen bears two spots of a darker hue, but which 

 disappear on looking at the creature with the head 

 pointing towards the observer. The thorax and 

 abdomen are fairly clad with tolerably short hairs, 

 the legs are cf the same colour as the abdomen, the 

 eyes a chocolate brown. The proboscis, for about 

 half its length, is fleshy ; the remaining portion, 

 towards the extremity, being considerably harder, but 

 scarcely chitinous. When dealt with microscopically, 

 ii will be found that the lobes of the labium, although 

 small, are capable of being expanded, and then 



impression that a minute molar is being observed. 

 These are all rather dark in colour, and, for the size 

 of the creature, very strong. 



A modification of the basal portions of the pseudo- 

 trachea form the secondary and third sets of teeth. 

 The bases spring from different parts, and become 

 united as they approach the free end. They are very 

 thin and delicate in structure. On comparing this 

 example with preceding illustrations, it will be 

 found to be by far the most minute yet dealt with, 

 yet a comparatively powerful set of organs are 

 presented ; in fact, it would appear that the size of 

 a fly has practically little to do with the general 

 arrangement beyond limiting the size of these organs, 

 but that the nature of the food has probably a much 

 closer bearing on the subject. 



PRESERVATION OF THE 

 EYESIGHT. 



I 



Fig. 180. — Teeth of Fucellafncorum. 



reveal a rather interesting set of organs of dentition. 

 These consist of primary, secondary, and third sets of 

 teeth in some portions of the mouth. Viewing them 

 in a lateral position, the primary set are six in 

 number, the two marginal members being of the same 

 type as the blow-fly ; then follow on one side (which 

 in its natural position is the fore part of the mouth), 

 two teeth somewhat similar, yet presenting a slight 

 change in form, inasmuch as one of the two points 

 which terminate the organ is considerably longer 

 than the other. One tooth of this form also succeeds 

 the lateral one at the back of the mouth, but it will 

 be observed the long point is here reversed. The 

 remaining tooth of the primary set is rather remark- 

 able, as it bears three points, and, when looked at 

 with an eighth of an inch power, conveys the 



OBSERVE with great pleasure 

 that one of the Christmas Annuals 

 has been printed on green paper with 

 the type in blue ink, with the praise- 

 worthy intention of saving the eye- 

 sight of readers. 



The subscribers to SciEN( £-GossiP 

 probably use their eyes more diligently 

 than most persons, both in reading, 

 drawing, working with the microscope, 

 and examining minute objects ; this is 

 a question therefore that interests them 

 nearly. 



I think it well to point out that, 

 while the book printed as I have de- 

 scribed may be better than similar 

 works printed upon dead white paper, 

 the colours of both the paper and the 

 type might be greatly improved. The 

 paper is too much of a bluish-green, 

 and the ink is too bright a blue. Were 

 the paper more of a yellowish-green, 

 and the type dark olive-green, the result would be 

 much more restful to the eyes. I find it is a great 

 benefit to read this book through glasses of a smoky 

 brown tint ; the letters appear a less vivid blue and 

 are much sharper defined. Furthermore, a great 

 benefit might be gained by using heavier type, that is, 

 not larger letters, but letters with the fine strokes 

 thicker than they are usually made. 



I believe the publishers of Science-Gossip have 

 already paid some attention to this question, and 

 I trust it will one day bring forth fruit. 



John Browning. 



We have received a series of six slides from Mr. 

 H. Vial, Crediton, containing admirable anatomical 

 sections, beautifully mounted. 



