IXDIAX DRAG ON FLIES. 471 



thoir abilomcn. ^Vith a little practice much of the colouration may be 

 preserved and the decomposition and destruction of the specimens entirely 

 prevented. The wholo prot-ess of decomposition depends on moisture and 

 the amount of food-stutl's anil, in the case of the females, ovae present in 

 the abdominal cavity so that if the latter be removed and the specimen be 

 nuiokly dried, j^ratifying results will be obtained. 



The insects liaving been killed in a cyanide bottle, should be dealt with 

 at the earliest opportunity and certainly not later than three or four hours 

 afterward. The pleural membrane is slit up with a pair of sharp-pointed 

 scissors as far as the proximal end of the 3rd abdominal segment and as 

 far posterior as the distal end of the 7th. The incisions should not bo 

 carried further or the sexual organs will be ruined, but if it be found that 

 the abdomen cannot be properly cleansed, as sometimes happens, the in- 

 cisions may be carried round the outer side of the sexual organs, which 

 thus escape damage. The upper part of the intestine and ovaries are 

 then seized and the whole drawn out by means of a pair of forceps. 

 Very little practice is needed to carry out this simple manoeuvre and it 

 will be found that about two dozen can be cleansed within an hour. The 

 specimens should then be mounted on setting boards and placed straight 

 into a drying-tin similar to those used for drying cigars where they may 

 be kept for two or three days for complete desiccation to take place. 



Tillyard recommends what will seem to most collectors a far from humane 

 method. He places the live insect in a paper packet and allows it to perish 

 from starvation thus giving it time to get rid of all the faecal contents of 

 its bowel. The mass of eggs in the female cannot however be got rid of so 

 easily. The insects are allowed to die and then set up on boards and dried 

 rapidlv by means of a small oven heated by a 'spirit-lamp. The latter part 

 of his method should be very effective as rapid drying seems so very essen- 

 tial for preserving the colours. In the larger forms, the abdomen having 

 been slit up may be cleansed very easily by holding it under a tap with a 

 good flush of water which will carry away all the contained viscera. Very 

 pretty results may be obtained by painting the insides of the abdominal 

 walls after the specimen is partially dried, and if a living specimen be used 

 as a copy, but the slightest differences will be noticed in the two after the 

 treated specimen has been dried. 



Specimens until they have been dried should be carefully bottled up or 

 protected with plenty of napthiline or they will be attacked by a small fly 

 which deposits its eggs in and around the thorax. Maggots rapidly hatch 

 from these and make their way into the tissues of the thorax and 

 ultimately completely ruin the specimen, the colours of which change to 

 a dark brown and the legs and head drop oft'. 



To stiffen the abdomen and prevent it from fracturing oft' when dried, an 

 old and well-known process, " bristling " should be performed on the insect 

 before drying. Hog's bristles, super-stout horse-hair or very fine copper 

 wire such as silk covered electric cables are made up of, may be used and 

 should be run in between the middle pair of legs and passed through the 

 thorax and carefully on to the end of the abdomen after which the excess 

 in front may be snipped off with scissors. 



vV 



O^iC/Q^ 



(To be continued.) 



