16 



HARDWICKE'S SCIENCE-GOSSIP. 



of bismuth and mastic varnish is given in " Davies 

 on Mounting," but I have not tried it. These 

 varnishes I know are against Dr. Carpenter's advice, 

 in the way of containing solid particles; but his 

 caution does not refer, I should say, to finishing 

 varnishes. In reference to mastic varnish, I saw a 

 statement some months back in Science-Gossip, 

 that gum mastic was not soluble in turpentine ; I 

 am certain this must be an error, if the turpentine is 

 good, as I have dissolved mastic myself in it. It is 

 not worth while, however, to do so, as it is easily 

 bought good from artists' colourmen.— /. G. P. 

 Vereker. 



The Reflex Illuminator. — Will some of the 

 readers of Science-Gossip give their experience in 

 the use of this piece of apparatus ? I have been 

 able to do the following: — with a ^ths, ith, and 

 xuth immersion by Gundlach, I get very good 

 results, on a dark field, with some few objects, as 

 insect scales and diatoms. Of the scales I succeed 

 best with Lepisma and Podura, the latter exhibiting 

 structure invisible by other modes of illumination. 

 With regard to diatoms, P. formosum, decorum, 

 and a few others come up well, even with the ^g-th 

 immersion, when mounted in balsam ; when dry, I 

 fail altogether. I have had a single specimen of 

 Heliopelta mounted for me ; this, under the Toth, 

 shows more beautifully than with the paraboloid. 

 Some of the Aulacodlsci exhibit quite a new appear- 

 ance when the light falls upon them under a certain 

 angle. All the objects require to be mounted on 

 clean slides, and with covers free from striae, and 

 the best effects are obtained when a single object 

 is in the field of view. I should think Mr. Kitton 

 might give us a hint, for I feel confident that its 

 powers are not yet developed. — P. 



Cement in Glycerine.— "J. It. T." appears to 

 doubt the efficacy of the cement recommended by 

 " E. K." for keeping in glycerine. I can with con- 

 fidence recommend it. I have found no other 

 cement to answer the purpose. There are two hun- 

 dred objects in my cabinets mounted in glycerine, 

 and sealed with gold-size, thickened with a mixture 

 of white and red lead and litharge. These were 

 mounted principally in 18G9 and 1870, and at present 

 they are all sound, with the exception of two, which 

 were defective from the first. It is curious that 

 " J. It. T." should use crocus of iron in his gold- 

 size in opposition to Dr. Carpenter's instructions. — 

 S. L. B. 



Interference of Light.— Some time ago I 

 was bothered in the same way as J. G. R. Powell, 

 by the reflection of light from the sides of the tube 

 of the microscope, when using the second eye-piece. 

 This was, however, completely done away with by 

 the insertion of a "stop" or " diaphragm " within 

 the tube, cutting off the reflected rays— B. B. W. 



ZOOLOGY. 



"Missing Links" among the Lepidoptera. — 

 M. Kiinckel has described in the " Comptes 

 Rendus" several Australian Lepidoptera which 

 possess terebrant trunks, instead of the usual suck- 

 ing probosces we have always regarded as charac- 

 teristic of the order. Having read in a newspaper 

 the depredations of a moth {Ophideres fullonica) on 

 oranges, he carefully examined the trunks of these 

 insects. Lepidoptera are specially constructed to 

 suck up the nectar of open flowers, and to imbibe 

 sweet fluids. M. Kiinckel goes on to say :— " By 

 a strange exception, the moths of the genus Ophi- 

 deres, Boisd., possess a rigid trunk — a true borer of 

 ideal perfection — capable of piercing the skins of 

 fruits, and of boring through the thickest and most 

 resistant envelopes. This trunk is a perfect instru- 

 ment, and wonld be an excellent model for the 

 making of new tools to be employed in boring holes 

 in various materials. Partaking at once of the 

 barbed lance, the gimlet, and the rasp, it can pierce, 

 bore, and tear, at the same time, allowing liquids to 

 pass without impediment by the internal canal. The 

 two applied maxillae terminate in a strong, sharp, 

 triangular point, furnished with two barbs ; they 

 then become enlarged, and present on the lower 

 surface three portions of the thread of a screw, 

 while their sides and their upper surface are covered 

 with short strong spines, projecting from the centre 

 of a depression with hard and abrupt margins. The 

 purpose of these spines is to tear the cells of the 

 orange-pulp, as the rasp serves to open the cells of 

 the beetroot, in order to extract the sugar from 

 them. The upper region of the trunk is covered 

 below and on the sides with fine close-set striae, 

 arranged in half-screws, which give it the properties 

 of a file ; the striae are interrupted here and there 

 by small spines of soft consistence, which serve for 

 the perception of tactile sensations. The orifice of 

 the canal through which the liquids ascend is situated 

 on the lower surface below the first screw-thread. 

 Not content with examining Ophideres fullonica, 

 Linn., I investigated all the representatives of the 

 genus, and found that 0. materna, Linn., 0. sala- 

 minia, Cram., 0. imperator, Boisd., as well as the 

 other species, have a powerful trunk in the form of 

 a borer. The structure of the maxillae, therefore, 

 furnishes a generic character of great value ; more- 

 over it establishes a closer relationship between the 

 Lepidoptera, the Hemiptera and certain Diptera 

 in which the maxillae are destined to pierce tissues. 

 The Australian colonists dread 0. fullonica on 

 account of the mischief caused by it in the orange 

 plantations ; for the fruits which it pierces with 

 holes quickly spoil, and soon fall to the ground and 

 rot. All the Lepidoptera of the genus Ophideres 

 being, as I have just shown, furnished with a tere- 

 brant trunk, it is incontestable that they have similar 



