HARD WICKE ' S S CIE NCE- G SSIP. 



57 



pin and the lowest part of the insect, so that the 

 forceps may be placed beneath the insect, which is 

 often necessary when the pins are very thin and 

 consequently liable to bend. 



By placing the specimen well up the pin, a much 

 higher magnifying power may be employed in its 

 observation when in the cabinet, and the more space 

 there is for the forceps both above and below the 

 insect, the less will be the chances of an accident. In 

 removing specimens from one box to another always 

 use a pair of forceps, the fingers are liable to crush 

 the fly, unless extreme caution is employed. 



If specimens are to be carded, care must be taken 

 not to let the wings touch the gum until the rest of 

 the insect is set, as it is difficult to move them when 

 once in the gum and, if elevated, they curl up in- 

 stantly, giving considerable trouble to reopen them. 



Use thin gum tragacanth for carding specimens, 

 and take care that the pubescence is not matted with 

 it during setting. 



Let me repeat here, however, that carding had 

 better be avoided entirely. 



After returning from an expedition, set all the 

 small flies first ; and here, perhaps, I should recom- 

 mend a method of killing them, for they should 

 always be brought home alive in chip-boxes. The 

 lids of the boxes should be slightly raised, so as to 

 admit the fumes of sulphur and the boxes ranged 

 round a small tin containing powdered sulphur. 

 Light the sulphur, and immediately cover the boxes 

 with a basin, allowing all to remain untouched for 

 half-an-hour. 



The insects will then be found dead and perfectly 

 relaxed. 



Never kill Diptera by dropping them into hot 

 water, or by means of chloroform, ammonia, or any 

 method that wets them, as the delicate pubescence if 

 once matted can never regain its original appearance. 



The larger Muscidce, all the Syrphidae and Asitidse 

 will easily remain relaxed, if placed in a tin half 

 filled with fine sand slightly moistened. 



The larger specimens may thus be retained un- 

 stiffened for a week or more after capture, but the 

 smaller species and all the Neurocera should be set 

 as soon as possible after their capture, the same day, 

 if convenient. 



In conclusion, I should like to make a suggestion 

 of a plan by which young collectors may add to their 

 own collections, and at the same time furnish me 

 with specimens of British Diptera. 



If they will collect and pin the specimens, giving 

 the locality and date of each, if possible, forwarding 

 them to me from time to time, and at the end of the 

 season will give me either a list of the species they 

 possess (of any order) or of their desiderata, I will 

 obtain and send in return species new to their 

 collection and of whatever order they may prefer. 



A few young entomologists of my acquaintance 

 have agreed to do this, and I am glad to state that 



I have already received several small consignments 

 of my favourite insects. 



Foreign Diptera, if obtainable, are equally accept- 

 able as British. 



Should unset and unpinned flies be sent, care 

 should be taken that the box is quite full, to prevent 

 the insects being shaken about during transit ; if this 

 rule be disregarded, much damage will be the result, 

 for the legs become so very brittle soon after death 

 that the least touch is often sufficient to break them 

 off. 



I have already extended my paper beyond the 

 limit originally fixed, and could with pleasure dilate 

 still further on the advantages of collecting Diptera, 

 giving directions for their capture and preservation, 

 so long as readers were to be found to peruse them. 



Sufficient hints, however, I believe will be found 

 in these notes to enable a beginner to collect Diptera, 

 and this being so the object of my efforts is attained. 



My last paragraph shall be — collect Diptera as 

 much as possible, as a favour to myself, if for no 

 other reason, and I will do my very best in return for 

 any one thus assisting me. 



GOSSIP ON CURRENT TOPICS. 

 By W. Mattieu Williams, F.R.A.S., F.C.S. 



EXPLOSION OF EGGS.— The description on 

 page 47 of last number of this magazine 

 reminds me of an experience of my own some years 

 ago. I had invented a method of preserving eggs, 

 which answered fairly well. This invention was 

 carried out by immersing the eggs for about half a 

 minute in a bath of melted wax or stearine, or better, 

 a mixture of these. This filled up the pores of the shell, 

 and the heat lined its inside with a varnish of coagulated 

 albumen ; the two combining to prevent the admis- 

 sion of air and consequent decomposition. I kept 

 some eggs thus prepared about six months, and sent 

 three of them to the kitchen to be cooked for break- 

 fast as usual. They all exploded in the water, the 

 direct effect of the explosions being much improved 

 by the quantity of water thrown into the fire. The 

 domestic was so much alarmed that she refused to 

 cook any more of " the master's eggs." I therefore 

 cooked the remainder myself, and demonstrated the 

 cause of the explosions by pricking pin-holes in the 

 shells of some, and leaving the others imperforated. 

 All the latter exploded, while those that were per- 

 forated passed through the ordeal of cookery as 

 usual, proving that it was the expansion of air or 

 vapour imprisoned within the egg by the air-tight 

 shell that caused the explosion. In the cases des- 

 cribed by Dr. Blair and Mr. Cross there was probably 

 an abnormal density and impermeability of shell. 

 That the ostrich egg should explode dangerously is 



