Collecting and Preserving Insects 



an occasional strip of moistened blotting paper inserted or they 

 may be enclosed in glass tubes with tight absorbent stoppers the 

 latter being occasionally moistened. Bees need very little mois- 

 ture and give very little trouble in rearing. Wood-boring in- 

 sects of all kinds may as a rule be kept perfectly dry or only 

 moistened every two or three weeks. Plant-bugs need simply 

 plenty of fresh food and take care of themselves with compara- 

 tive indifference as to their surroundings. 



Of all larvae none are more difficult to rear than those of the 

 the saw-flies. Their mouth-parts seem to dry unless constantly 

 lubricated by the saliva produced by mastication and once dried 

 the larva usually dies. Fresh food must constantly be supplied 

 and if possible they must not be allowed to descend to the sur- 

 face of the sand; the latter must be carefully covered with 

 paper, for if they once close their prolegs on a grain of sand 

 they hold it convulsively and it is almost impossible to dislodge 

 it so that they are practically unfitted for again clasping a 

 twig. 



The study of scale insects is a simple one. The food plants 

 should be grown in pots and the insects colonized upon it. 

 Most of the species remain stationary or nearly so and their loca- 

 tion recorded, the exact situation of each individual under 

 observation being circumscribed by a ring of ink marked with a 

 pen upon the leaf. 



The Aquarium. Almost any of the different styles of 

 aquaria which may be purchased will answer a good purpose. 

 A very good one is shown in the accompanying illustration. 

 Where it is desired to go rather thoroughly into the rearing of 

 aquatic insects and where one is able to spend some money in 

 preparations, the apparatus in use in my office is rather better 

 than anything which I have seen. Two glass aquaria each 

 2^2 x \Y* x \y 2 are placed end to end, the one elevated on a three 

 inch base so as to make it that much higher than the other. The 

 water connections from the one to the other are so arranged that 

 each may be independent of the other, and the details are simply 

 arranged. In each is a V-shaped inclined glass septum with a 

 broad, deflexed lip, and beneath this lip has been constructed an 

 artificial rock-work grotto. The water enters the first aquarium 

 through a T sprinkler with six pipette orifices. It drops a distance 

 of six or eight inches into the V-shaped septum and its force is 



399 



