44 



BULLETIN 67, UNITED STATES NATIONAL MUSEUM. 



60° to 100°. On top of the funnel there is placed a sort of square tray of metallic net- 

 work (a sieve) upon which is placed the material to be examined, and this material 

 should naturally be sufficiently humid to restrain the living insects from escaping. 

 Whether the material in the tray, passing gradually (although rapidly enough) through 

 and losing some of its moisture causes the insects to fall to the bottom, or whether these 

 are attracted by the heat beneath, it is certain that they all try to reach the metallic 

 net and there they pass through, falling into the metallic funnel. 



But the walls of the funnel, thanks to the water surrounding them, are so warm that 

 the insects can not remain, and they fall, rolling downward until they enter the tube 

 containing alcohol, in which only a very small quantity of detritus is collected. 



It is necessary, however, not to 

 shake or stir the apparatus or the 

 material during this operation, to 

 avoid the falling of too much detritus 

 together with the insects. 



The diameter of the funnel should 

 be about a half meter, and the tray 

 itself should be movable in order that 

 it may be refilled with the material 

 when separated from the funnel. 



I have used to great advantage a 

 small apparatus of this style (the fun- 

 nel being only 30 centimeters in di- 

 ameter) during the last year, and 

 have thus discovered several new 

 species of Italian Acarida, illustrated 

 in this journal, while I have collected 

 an enormous quantity of other small 

 arthropods, especially of Collembola, 

 Symphyla, Pauropoda, etc. 



These, especially the Collembola, 

 and also the Thysanura, all remain 

 on the surface of the alcohol, not be- 

 coming submerged, while the other 

 insects all fall to the bottom of the 

 tube. 



Thus, it is easy to collect the said 

 Collembola with a brush from the 

 surface of the alcohol without further 

 disturbance. 



After the excellent results secured 



from the small apparatus referred 



constructed which has been operated since 



Fig. SO. —The Berlese collecting trap: A, Exterior 



RECEPTACLE CONTAINING WATER; B, INTERIOR FUNNEL; 



C, VESSEL HAVING THE BOTTOM OF METALLIC NETWORK; 



D, SUBSTANCE FOR EXAMINATION; E, FUNNEL FOR IN- 

 TRODUCING THE WATER; F, SMALL GLASS TUBE CON- 

 TAINING ALCOHOL, WHERE THE INSECTS ARE COLLECTED, 

 THIS BEING CONNECTED TO THE APEX OF THE FUNNEL 

 BY A SHORT TUBE (a) OF INDIA RUBBER; G, FEET SUP- 

 PORTING THE APPARATUS; L, LAMP FOR HEATING; M, 



India rubber tube for carrying off the gas; N, 



FAUCET FOR DISCHARGE. 



to, I had another, much larger, 

 November. 



It is composed of a case of wood, the interior of which is covered with lead, and 

 has a capacity of 6 hectoliters, and contains four large funnels in square sections, the 

 sides of which are 50 centimeters. Thus I have an extent of 1 square meter upon 

 which to arrange the material for examination, and I can place four different kinds of 

 material from four different localities on these sieves. 



The water is about 3 hectoliters and is kept at 60° or 70°, and for some hours the 

 temperature is maintained by means of a large gas heater. 



This heater, which serves me well also for heating the room in which it is placed, 

 consumes about 3 cubic meters of gas per day, which proves that, with an expense of 

 about 1 lira, I daily obtain, without any trouble, a greater number of small insects 



